Vinylene compounds and liquid-crystal composition

ABSTRACT

Liquid crystalline compounds which have a wide temperature range of liquid crystal phase, low viscosity, and improved threshold voltage; liquid crystal compositions; and liquid crystal display devices comprising the composition can be provided; and the liquid crystalline compounds are expressed by the general formula (1) 
     
       
         Ra—A 1 —Z 1 —A 2 —Z 2 —A 3 —(Z 3 —A 4 ) m —Rb  (1) 
       
     
     wherein Ra represents an alkyl group having 1 to 20 carbon atoms one or more —CH 2 — in which alkyl group may be replaced by —O— or the like, and one or more hydrogen atoms in which alkyl group may be replaced by a halogen atom; Rb represents Ra, a halogen atom, or cyano group; A 1 , A 2 , A 3 , and A 4  independently represent a divalent ring group; Z 1 , Z 2 , and Z 3  independently represent an alkenylene group having 2 to 4 carbon atoms, —COO—, a covalent bond, or the like provided that at least one of Z 1  to Z 3  represents an alkenylene group having 2 to 4 carbon atoms, and at least one of Z 1  to Z 3  represents —COO— or —OCO—; and m is 0 or 1.

TECHNICAL FIELD

The present invention relates to a liquid crystalline compound andliquid crystal composition. More specifically, it relates to a novelliquid crystalline compound which has an alkenylene group having 2 to 4carbon atoms and ester bond as bonding group at the same time, relatesto a liquid crystal composition comprising the compound, and relates toa liquid crystal display device comprising the liquid crystalcomposition.

BACKGROUND ART

Liquid crystal display devices comprising liquid crystalline compounds(the term “liquid crystalline compound” as used hereinafter is intendedto use as a general name for compounds exhibiting a liquid crystalphase, or compounds which do not exhibit a liquid crystal phase but areuseful as a component of liquid crystal compositions) are widely used indisplays such as watches, tabletop calculators, and word processors.These display devices utilize optical anisotropy and dielectricanisotropy of liquid crystalline compounds.

Liquid crystal phase includes nematic liquid crystal phase, smecticliquid crystal phase, and cholesteric liquid crystal phase, and displaydevices utilizing nematic liquid crystal phase are most widely used.

As display mode using a liquid crystal, there have been devised dynamicscattering (DS) mode, deformation of aligned phases (DAP) mode,guest/host (GH) mode, twisted nematic (TN) mode, super twisted nematic(STN) mode, and thin film transistor (TFT) mode.

Liquid crystalline compounds used in these display devices have toexhibit liquid crystal phase in a wide temperature range with roomtemperature being its center, have to be sufficiently stable underconditions in which the display devices are used, and have to haveproperties sufficient to drive the display devices. However, no liquidcrystalline compounds which satisfy these requirements by a singlecompound have been found up to now. Accordingly, it is actualcircumstances that several kind or several tens kind of liquidcrystalline compounds are mixed to produce liquid crystal compositionshaving required properties. These liquid crystal compositions arerequired to be stable against moisture, light, heat, and air whichusually present under conditions in which the display devices are used,required to be stable against electric field and electromagneticradiation, and further required to be chemically stable against thecompounds to be mixed. The liquid crystal compositions are required tohave proper values of such physical properties as optical anisotropy(Δn) and dielectric anisotropy (Δε) depending on display mode and theshape of display devices. Further, it is important that each componentin the liquid crystal compositions has an excellent solubility with oneanother.

Especially, it is desired to still more lower threshold voltage whichlargely contributes to high speed response necessary for expanding thesize of screen of liquid crystal display, and contributes to saving ofelectric power (E. Jakeman et al., Phys. Lett., 39A. 69 (1972)). For thehigh speed response, low viscosity of the compositions is alsoimportant. Moreover, environments in which liquid crystal displaydevices are used are diversified in recent years, and keeping with suchcircumstance, development of liquid crystalline compounds which exhibitliquid crystal phase in a wider temperature range is earnestly desired.

In order to achieve these purposes, various compounds have heretoforebeen developed, for instance, the compound expressed by the followingformula (a) or (b) is proposed in Laid-open Japanese Patent PublicationNo. Hei 4-279560, and the compound expressed by the following formula(c) is proposed in Japanese Patent Publication No. Hei 7-72148,respectively.

However, the compound expressed by the formula (a) can not be said to besufficiently wide in temperature range of liquid crystal phase, and thecompound expressed by the formula (b) has a problem that its viscosityis high.

Whereas the compound expressed by the formula (c) is a three ringcompound containing an alkenylene group as bonding group, its disclosureis insufficient. That is, the physical properties of the compound arenot shown, and besides, specific data are not disclosed at all about theutility expected when it is used as a component of liquid crystalcompositions.

DISCLOSURE OF THE INVENTION

An object of the present invention is to remove the problems in thebackground art described above. Another object of the present inventionis to provide novel liquid crystalline compounds which are wide intemperature range of liquid crystal phase, are low in viscosity, have alow threshold voltage, and are excellent in stability and mutualsolubility with other liquid crystal materials, to provide liquidcrystal compositions comprising the liquid crystalline compound, and toprovide liquid crystal display devices comprising the liquid crystalcomposition.

The present invention for achieving the purposes described above issummarized as follows:

(1) A vinylene compound expressed by the general formula (1)

Ra—A₁—Z₁—A₂—Z₂—A₃—(Z₃—A₄)_(m)—Rb  (1)

wherein Ra represents an alkyl group having 1 to 20 carbon atoms one ormore —CH₂— in which alkyl group may be replaced by —O—, —S—, —CO—,—CH═CH—, or —C═C—, but in no case —O— and/or —S— continues, and one ormore hydrogen atoms in which alkyl group may be replaced by a halogenatom; Rb represents Ra, a halogen atom, or cyano group; A₁, A₂, A₃, andA₄ independently represent trans-1,4-cyclohexylene group,cyclohexenylene group, 1,4-phenylene group one or more hydrogen atoms onwhich ring may be replaced by a halogen atom or cyano group,pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, or1,3-dioxane-2,5-diyl group; Z₁, Z₂, and Z₃ independently represent analkenylene group having 2 to 4 carbon atoms, —COO—, —OCO—, —(CH₂)₂—,—C≡C—, —CH₂O—, —OCH₂—, or a covalent bond provided that at least one ofZ₁ to Z₃ represents an alkenylene group having 2 to 4 carbon atoms, andat least one of Z₁ to Z₃ represents —COO— or —OCO—; and m is 0 or 1.

(2) The vinylene compound recited in (1) above wherein m is 0.

(3) The vinylene compound recited in (1) above wherein m is 1.

(4) The vinylene compound recited in (2) above wherein either Z₁ or Z₂is vinylene or butenylene.

(5) The vinylene compound recited in (3) above wherein either Z₁ or Z₂is vinylene or butenylene.

(6) The vinylene compound recited in (4) above wherein A₁ and A₂ areindependently trans-1,4-cyclohexylene group, or 1,4-phenylene group oneor more hydrogen atoms on which ring may be replaced by a halogen atomor cyano group.

(7) The vinylene compound recited in (5) above wherein A₁ and A₂ areindependently trans-1,4-cyclohexylene group, or 1,4-phenylene group oneor more hydrogen atoms on which ring may be replaced by a halogen atomor cyano group.

(8) A liquid crystal composition comprising at least one vinylenecompound recited in any one of (1) to (7) above.

(9) A liquid crystal composition comprising, as a first component, atleast one vinylene compound recited in any one of (1) to (7) above, andcomprising, as a second component, at least one compound selected fromthe group consisting of the compounds expressed by any one of thegeneral formulas (2), (3), and (4)

wherein R₁ represents an alkyl group having 1 to 10 carbon atoms; X₁represents F, Cl, OCF₃, OCF₂H, CF₃, CF₂H, or CFH₂; L₁, L₂, L₃, and L₄independently represent H or F; Z₄ and Z₅ independently represent—(CH₂)₂—, —CH═CH—, or a covalent bond; and a is 1 or 2.

(10) A liquid crystal composition comprising, as a first component, atleast one vinylene compound recited in any one of (1) to (7) above, andcomprising, as a second component, at least one compound selected fromthe group consisting of the compounds expressed by any one of thegeneral formulas (5), (6), (7), (8), and (9)

wherein R₂ represents F, an alkyl group having 1 to 10 carbon atoms, oran alkenyl group having 2 to 10 carbon atoms any methylene group (—CH₂—)in which alkyl or alkenyl group may be replaced by oxygen atom (—O—),but in no case two or more methylene groups are continuously replaced byoxygen atom; ring A represents trans-1,4-cyclohexylene group,1,4-phenylene group, or 1,3-dioxane-2,5-diyl group; ring B representstrans-1,4-cyclohexylene group, 1,4-phenylene group, orpyrimidine-2,5-diyl group; ring C represents trans-1,4-cyclohexylenegroup or 1,4-phenylene group; Z₆ represents —(CH₂)₂—, —COO—, or acovalent bond; L₅ and L₆ independently represent H or F; and b and c areindependently 0 or 1,

wherein R₃ represents an alkyl group having 1 to 10 carbon atoms, L₇represents H or F; and d is 0 or 1,

wherein R₄ represents an alkyl group having 1 to 10 carbon atoms; ring Dand ring E independently represent trans-1,4-cyclohexylene group or1,4-phenylene group; Z₇ and Z₈ independently represent —COO— or acovalent bond; Z₉ represents —COO— or —C≡C—; L₈ and L₉ independentlyrepresent H or F; X₂ represents F, OCF₃, OCF₂H, CF₃, CF₂H, or CFH₂; ande, f, and g are independently 0 or 1,

wherein R₅ and R₆ independently represent an alkyl group having 1 to 10carbon atoms or an alkenyl group having 2 to 10 carbon atoms anymethylene group (—CH₂—) in which alkyl or alkenyl group may be replacedby oxygen atom (—O—), but in no case two or more methylene groups arecontinuously replaced by oxygen atom; ring G representstrans-1,4-cyclohexylene group, 1,4-phenylene group, orpyrimidine-2,5-diyl group; ring H represents trans-1,4-cyclohexylenegroup or 1,4-phenylene group; Z₁₀ represents —C≡C——COO—, —(CH₂)₂—,—CH═CH—C≡C—or a covalent bond; and Z₁₁ represents —COO— or a covalentbond,

wherein R₇ and R₈ independently represent an alkyl group having 1 to 10carbon atoms or an alkenyl group having 2 to 10 carbon atoms anymethylene group (—CH₂—) in which alkyl or alkenyl group may be replacedby oxygen atom (—O—), but in no case two or more methylene group arecontinuously replaced by oxygen atom; ring I representstrans-1,4-cyclohexylene group, 1,4-phenylene group, orpyrimidine-2,5-diyl group; ring J represents trans-1,4-cyclohexylenegroup, 1,4-phenylene group one or more hydrogen atoms on which ring maybe replaced by F, or pyrimidine-2,5-diyl group; ring K representstrans-1,4-cyclohexylene group or 1,4-phenylene group; Z₁₂ and Z₁₄independently represent —COO—, —(CH₂)₂—, or a covalent bond; Z₁₃represents —CH═CH—, —C≡C—, —COO—, or a covalent bond; and h is 0 or 1.

(11) A liquid crystal composition comprising, as a first component, atleast one vinylene compound recited in any one of (1) to (7) above,comprising, as a part of a second component, at least one compoundselected from the group consisting of the compounds expressed by any oneof the general formulas (2), (3), and (4), and comprising, as anotherpart of the second component, at least one compound selected from thegroup consisting of the compounds expressed by any one of the generalformulas (5), (6), (7), (8), and (9).

(12) A liquid crystal display device comprising the liquid crystalcomposition recited in any one of (8) to (11) above.

Liquid crystalline vinylene compounds of the present invention expressedby the general formula (1) are wide in temperature range of liquidcrystal phase, are low in viscosity, and have a low threshold voltage.These liquid crystalline compounds are sufficiently stable chemicallyand physically under the conditions in which liquid crystal displaydevices are ordinarily used. Further, liquid crystalline compoundshaving desired physical properties can be obtained by selecting properrings, substituents and/or bonding groups from molecule formingelements.

Accordingly, when the compounds of the present invention are used ascomponent of liquid crystal compositions, novel liquid crystalcompositions having preferable properties can be provided.

Liquid crystalline compounds of the present invention expressed by thegeneral formula (1) are classified as shown below. In the formulas shownbelow, ak represents an alkenylene group having 2 to 4 carbon atoms, Erepresents ester bond, and Ra, Rb, A₁ to A₄, and Z₁ to Z₃ have the samemeaning as defined above.

Compounds having three six-membered rings:

Ra—A₁—ak—A₂—E—A₃—Rb  (1a)

Ra—A₁—E—A₂—ak—A₃—Rb  (1b)

Compounds having four six-membered rings:

Ra—A₁—A₂—ak—A₃—E—A₄—Rb  (1c)

Ra—A₁—A₂—E—A₃—ak—A₄—Rb  (1d)

Ra—A₁—ak—A₂—A₃—E—A₄—Rb  (1e)

Ra—A₁—E—A₂—A₃—ak—A₄—Rb  (1f)

Ra—A₁—ak—A₂—E—A₃—A₄—Rb  (1g)

Ra—A₁—E—A₂—ak—A₃—A₄—Rb  (1h)

Ra—A₁—ak—A₂—ak—A₃—E—A₄—Rb  (1i)

Ra—A₁—E—A₂—ak—A₃—ak—A₄—Rb  (1j)

Ra—A₁—(CH₂)₂—A₂—ak—A₃—E—A₄—Rb  (1k)

Ra—A₁—ak—A₂—(CH₂)₂—A₂—E—A₄—Rb  (1l)

Ra—A₁—ak—A₂—E—A₃—(CH₂)₂—A₄—Rb  (1m)

Ra—A₁—E—A₂—ak—A₃—(CH₂)₂—A₄—Rb  (1n)

 Ra—A₁—C≡C—A₂—ak—A₃—E—A₄—Rb  (1o)

Ra—A₁—ak—A₂—C≡C—A₃—E—A₄—Rb  (1p)

Ra—A₁—ak—A₂—E—A₃—C≡C—A₄—Rb  (1q)

Ra—A₁—CH₂O—A₂—ak—A₃—E—A₄—Rb  (1r)

Ra—A₁—ak—A₂—CH₂O—A₃—E—A₄—Rb  (1s)

Ra—A_(1—ak—A) ₂—E—A₃—CH₂O—A₄—Rb  (1t)

Ra—A₁—OCH₂—A₂—ak—A₃—E—A₄—Rb  (1u)

Ra—A₁—ak—A₂—OCH₂—A₃—E—A₄—Rb  (1v)

Ra—A₁—ak—A₂—E—A₃—OCH₂—A₄—Rb  (1w)

While the compounds expressed by one of the formulas (1a) to (1w) arepreferable, the compounds expressed by one of the following formulas(1Xa) to (1Xq) are especially preferable among the former compounds:

wherein Ra, Rb, A₂ to A₄, Z₂, Z₃, and m have the same meaning asdescribed above.

As described above, the liquid crystalline compounds of the presentinvention are expressed by the general formula (1).

In the formula, Ra is a straight chain or branched alkyl group having 1to 20 carbon atoms. As the straight chain alkyl group, methyl, ethyl,propyl, butyl, pentyl, hexyl, heptyl, decyl, pentadecyl, and icosyl canspecifically be mentioned. As the branched alkyl group, isopropyl,2-methylbutyl, sec-butyl, tert-butyl, isopentyl, isohexyl, 3-ethyloctyl,3,8-dimethyltetradecyl, and 5-ethyl-5-methylnonadecyl can specificallybe mentioned. The branched alkyl groups described above may be oneswhich exhibit an optical activity.

One or more —CH₂— in these alkyl groups may be replaced by —O—, —S—,—CO—, —CH═CH—, or —C≡C—, unless —O— and/or —S— continues. Among thealkyl groups, alkoxy groups and alkoxyalkyl groups can be mentioned asexamples in which —CH₂— is replaced by —O—; alkylthioalkyl groups asexamples in which —CH₂— is replaced by —S—; alkenyl groups,alkoxyalkenyl groups, alkenyloxy groups, alkenyloxyalkyl groups, andalkadienyl groups as examples in which —CH₂— is replaced by —CH═CH—; andalkynyl groups, alkynyloxy groups, and alkoxyalkynyl groups as examplesin which —CH₂— is replaced by —C≡C—. One or more hydrogen atoms in thealkyl groups described above may be replaced by a halogen atom, andhalogen substituted alkyl groups, halogen substituted alkoxy groups,halogen substituted alkenyl groups, and halogen substituted alkynylgroups can be mentioned as their examples.

Specific examples of these substituted alkyl groups are as follows:

As alkoxy groups, such groups as methoxy, ethoxy, propoxy, butoxy,pentyloxy, and nonyloxy,

as alkoxyalkyl groups, such groups as methoxymethyl, methoxyethyl,methoxypropyl, methoxybutyl, methoxypentyl, methoxyoctyl, ethoxymethyl,ethoxyethyl, ethoxypropyl, ethoxyhexyl, propoxymethyl, propoxyethyl,propoxypropyl, propoxypentyl, butoxymethyl, butoxyethyl, butoxybutyl,pentyloxymethyl, pentyloxybutyl, hexyloxymethyl, hexyloxyethyl,hexyloxypropyl, heptyloxymethyl, and octyloxymethyl,

as alkylthioalkyl groups, such groups as methylthiomethyl,methylthioethyl, methylthiopropyl, methylthiobutyl, methylthiooctyl,ethylthiomethyl, ethylthioethyl, ethylthioheptyl, propylthiomethyl,propylthioethyl, propylthiopropyl, propylthiopentyl, hexylthiomethyl,and heptylthioethyl,

as the groups in which —CO— substituted, such groups as methylcarbonyl,ethylcarbonyl, propylcarbonyl, methoxycarbonyl, ethoxycarbonyl,propoxycarbonyl, butoxycarbonyl, heptyloxycarbonyl, 2-oxopropyl,2-oxobutyl, 3-oxobutyl, 2-oxopentyl, 4-oxopentyl, 3-oxohexyl,5-oxohexyl, 2-oxoheptyl, 3-oxoheptyl, 6-oxoheptyl, 2-oxooctyl,4-oxooctyl, 7-oxooctyl, 3-oxononyl, 6-oxononyl, 8-oxononyl, 2-oxodecyl,5-oxodecyl, and 9-oxodecyl,

as alkenyl groups, such groups as vinyl, propenyl, butenyl, pentenyl,hexenyl, and decenyl,

as alkoxyalkenyl groups, such groups as methoxypropenyl, ethoxypropenyl,pentyloxypropenyl, methoxybutenyl, ethoxybutenyl, pentyloxybutenyl,methoxypentenyl, propoxypentenyl, methoxyhexenyl, propoxyhexenyl,methoxyheptenyl, and methoxyoctenyl,

as alkenyloxy groups, such groups as propenyloxy, butenyloxy,pentenyloxy, octenyloxy, and propenyloxymethyl,

as alkenyloxyalkyl groups, such groups as propenyloxyethyl,propenyloxybutyl, butenyloxymethyl, butenyloxyethyl, butenyloxypentyl,pentenyloxymethyl, pentenyloxypropyl, hexenyloxymethyl, hexenyloxyethyl,heptenyloxymethyl, and octenyloxymethyl,

as alkadienyl groups, such groups as butadienyl, pentadienyl,hexadienyl, heptadienyl, octadienyl, and icosadienyl,

as alkynyl groups, such groups as ethynyl, propynyl, butynyl, pentynyl,and octynyl,

as alkynyloxy groups, such groups as ethynyloxy, propynyloxy,butynyloxy, pentynyloxy, and tetradecynyloxy,

as alkoxyalkynyl groups, methoxypropynyl, methoxypentynyl,ethoxybutynyl, propoxypropynyl, hexyloxyheptynyl, methoxymethylbutynyl,methoxypropylethynyl, and butoxymethylpropynyl,

as halogen substituted alkyl groups, such groups as fluoromethyl,difluoromethyl, trifluoromethyl, 2-fluoroethyl, 1,2-difluoroethyl,1,1,2,2-tetrafluoroethyl, 2-bromo-1,2-difluoroethyl, 3-fluoropropyl,1,2,3,3-tetrafluoropropyl, 1,1,2,3,3,3-hexafluoropropyl, 4-fluorobutyl,1,1,2,4-tetrafluorobutyl, 5-fluoropentyl, 2,3,3,4,5-pentafluoropentyl,6-fluorohexyl, 2,3,4,6-tetrafluorohexyl, 7-fluoroheptyl, and8,8-difluorooctyl,

as halogen substituted alkoxy groups, such groups as difluoromethoxy,trifluoromethoxy, 1,1-difluoroethoxy, 2,2-difluoroethoxy,2,2,2-trifluoroethoxy, 1,1,2,2-tetrafluoroethoxy, perfluoroethoxy,1,1,2,3,3,3-hexafluoropropoxy, and perfluoropropoxy, and

as halogen substituted alkenyl groups, such groups as 3-fluoropropenyl,4-fluoro-1-butenyl, 4-fluoro-2-butenyl, 5-fluoro-1-pentenyl,5-fluoro-2-pentenyl, 5-fluoro-3-pentenyl, 6-fluoro-1-hexenyl,6-fluoro-3-hexenyl, 7-fluoro-5-heptenyl, 2,2-difluorovinyl,1,2-difluorovinyl, 2-chloro-2-fluorovinyl, 2-bromo-2-fluorovinyl,2-fluoro-2-cyanovinyl, 3,3-difluoro-2-propenyl,3-chloro-3-fluoro-1-propenyl, 2,3-difluoro-1-propenyl,1,3-difluoro-2-propenyl, 1,3,3-trifluoro-2-propenyl,1,2,4,4-tetrafluoro-3-butenyl, 5,5-difluoro-4-pentenyl,3,3-difluoro-5-hexenyl, and 8,8-difluoro-7-octenyl.

While Rb is a group selected from the Ra described above, a memberselected from halogen atoms including F, Cl, Br, and I, or cyano group,it is preferably F, Cl, or cyano group from the viewpoint, for example,of stability.

A₁, A₂, A₃, and A₄ are independently selected fromtrans-1,4-cyclohexylene group, cyclohexenylene group, 1,4-phenylenegroup one or more hydrogen atoms on which ring may be replaced by ahalogen atom or cyano group, pyridine-2,5-diyl group,pyrimidine-2,5-diyl group, or 1,3-dioxane-2,5-diyl group.

Among the groups in which one or more hydrogen atoms may be replaced bya halogen atom or cyano group, for example, 2-fluoro-1,4-phenylene,3-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene,3,5-difluoro-1,4-phenylene, 2,3-5-trifluoro-1,4-phenylene,2-chloro-1,4-phenylene, 3-chloro-1,4-phenylene,2,3-dichloro-1,4-phenylene, 3,5-dichloro-1,4-phenylene,3-bromo-1,4-phenylene, 2-iodo-1,4-phenylene,2-chloro-3-fluoro-1,4-phenylene, 3-fluoro-5-chloro-1,4-phenylene,2-cyano-1,4-phenylene, 3-cyano-1,4-phenylene, and2,3-dicyano-1,4-phenylene can be mentioned as examples in which the ringis 1,4-phenylene.

At least one of Z₁, Z₂, and Z₃ is an alkenylene group having 2 to 4carbon atoms, vinylene or butenylene can be mentioned as theirpreferable examples, and the vinylene or butenylene in which alkenylenegroup is in trans form can be mentioned as more preferable examples.

Compounds of the present invention expressed by the general formula (1)and constituted by the groups selected from the Ra, Rb, A₁ to A₄, and Z₁to Z₃ described above have preferable properties. Among them, thecompounds which do not have two or more rings containing a hetero atom,and are expressed by one of the formulas (1Xa) to (1Xq) are morepreferable.

As more specific examples of these compounds, the ones expressed by oneof the following formulas (1-1) to (1-47) can be mentioned:

wherein Ra and Rb have the same meaning as described above, and hydrogenatom on the ring may independently be replaced by the atom or groupshown in the parenthesis.

Compounds of the present invention expressed by the general formula (1)can easily be produced by known general methods of organic synthesis,for instance, by the following methods:

wherein Ra, Rb, A₁ to A₄, Z₃, and m have the same meaning as describedabove.

For instance, a compound (1) which is an example of the compounds of thepresent invention can be produced by reacting a carboxylic acidderivative (2) with an alcohol (including phenol) derivative (3) in asolvent such as dichloromethane and chloroform in the presence of adehydrating agent such as dicyclohexylcarbodiimide (DCC) and4-dimethylaminopyridine (DMAP) (B. Neises et al., Organic Synthesis, 63,183 (1985)).

The compound (1) can also be produced by the method of E. J. Corey etal. (The Journal of Organic Chemistry, 38, 3223 (1973)), that is, byconverting the carboxylic acid derivative (2) described above into acompound (4) with a halogenating agent such as thionyl chloride in thepresence or absence of a solvent such as toluene and benzene, and thenreacting the compound (4) with the alcohol derivative (3) describedabove. This reaction is carried out at a temperature from roomtemperature to the boiling point of the solvent and under an inert gasatmosphere, more preferably, for accelerating the reaction, in thepresence of a base such as pyridine, triethylamine (B. Iselin et al.,Helvetica Chimica Acta, 40, 373 (1957)), dimethylaniline (C. Raha,Organic Synthesis, IV, 263 (1963)), or tetramethylurea (M. S. Newman etal., Tetrahedron Letters, 3267 (1967)).

Introduction of carbonyloxy group to the carboxylic acid derivative (2)used as a starting material in the reaction described above can beperformed by known general procedures of organic synthesis or theircombination. For instance, it can readily be carried out by such methodsas the hydrolysis of a nitrile derivative (R. C. Fuson et al., OrganicSynthesis, III, 557 (1955); and P. C. Baraldi et al., The Journal ofOrganic Chemistry, 50, 23 (1985)), the reaction of a Grignard reagent orlithium compound with carbon dioxide (H. Gilman et al., OrganicSynthesis, I, 361 (1941); and Y. Fukuyama et al., Synthesis, 443(1974)), the hydrolysis of an acid halide (N. O. V. Sonntag, ChemicalReview, 52, 237 (1953)), or the oxidation of an alkyl, alcohol, oraldehyde derivative (L. Friedman, Organic Synthesis, V, 810 (1973); E.Turos et al., Journal of the American Chemical Society, 111, 8231(1989); R. L. Shriner et al., Organic Synthesis, II, 538 (1943); D.Vakentine, Jr. et al., The Journal of Organic Chemistry, 45, 3698(1980); E. Dalcanale et al., The Journal of Organic Chemistry, 51, 567(1986); and E. J. Corey et al., Tetrahedron Letters, 399 (1979).

Introduction of —CH═CH— can readily be carried out, for instance, by theWittig reaction (Organic Reactions, Vol. 14, Chapter 3), theWittig-Schlosser reaction (M. Schlosser et al., Angew. Chem.,International Edition in English, 5, 126 (1966), or the Wittig-Hornerreaction (J. I. G. Cadogan, Organophosphorus Reagents in OrganicSynthesis, Academic (1979)).

That is, compounds in which —CH═CH— is introduced can be produced byreacting an aldehyde with a phosphonium salt in a solvent such astetrahydrofuran and diethyl ether in the presence of a base such aspotassium-tert-butoxide (t-BuOK) and n-butyl lithium. This reaction ispreferably carried out at a temperature from room temperature to −50° C.under an inert gas atmosphere. It is possible to isomerize the compoundsthus obtained by reacting them with benzenesulfinic acid orp-toluenesulfinic acid.

Further, —CH═CH— can be introduced by a method in which a vinyl Grignardreagent and a halide are subjected to a coupling reaction in thepresence of a catalyst such as Pd(PPh₃)₄, PdCl₂(PPh₃)₂, or NiCl₂(dppp)(T. V. Lee et al., Tetrahedron Letters, 46, 921 (1990)), or a method inwhich an aldehyde and a Grignard reagent are reacted, and the productthus formed is heated to dehydrate in a solvent such as toluene andxylene in the presence of an acidic catalyst such as p-toluenesulfonicacid.

Introduction of —C≡C— can be carried out, for instance, by the method ofW. Tao et al. (The Journal of Organic Chemistry, 55, 63 (1990), that is,by reacting an acetylene derivative with a halide in an alkylaminesolvent such as diethylamine and triethylamine in the presence of acopper iodide and a Pd catalyst such as Pd(PPh₃)₄ and PdCl₂(PPh₃)₂. Thisreaction is preferably performed at a temperature from room temperatureto the boiling point of the solvent and under an inert gas atmosphere.It can be introduced also by the Castro reaction (M. D. Raush et al.,The Journal of Organic Chemistry, 34, 468 (1969).

Introduction of —O— can be carried out, for instance, by reacting ahalide with an alcohol or phenol derivative in a solvent such asdimethyl sulfoxide, dimethyl formamide, 1,2-dimethoxyethane,tetrahydrofuran, hexamethylphosphoric acid triamide, and toluene in thepresence of a base such as sodium amide (J. B. Wright et al., Journal ofthe American Chemical Society, 70, 3098 (1948)), potassium carbonate (W.T. Olson et al., Journal of the American Chemical Society, 69, 2451(1947)), triethylamine (R. L. Merker et al., The Journal of OrganicChemistry, 26, 5180 (1961), sodium hydroxide (C. Wilkins, Synthesis,1973, 156), potassium hydroxide (J. Rebek et al., The Journal of OrganicChemistry, 44, 1485 (1979), barium hydroxide (Kawabe et al., The Journalof Organic Chemistry, 37, 4210 (1972)), or sodium hydride (C. J. Stark,Tetrahedron Letters, 22, 2089 (1981); and K. Takai et al., TetrahedronLetters, 21, 1657 (1980)).

While general methods for producing the compounds of the presentinvention are described above, more specific examples for producingstarting materials, carboxylic acid derivatives and alcohol derivativesare described below.

Production of carboxylic acid derivatives:

As shown in scheme 1, compound (5) which is prepared by a methoddescribed, for example, in Japanese Patent Publication No. Hei 7-2653 isconverted into compound (6) by reacting with an alcohol such as methanoland ethanol in the presence of pyridinium dichromate (PDC).Subsequently, this compound is reacted with methoxymethylphosphoniumchloride (MOTP) in the presence of a base such aspotassium-tert-butoxide (t-BuOK) and then deprotected with a dilutedhydrochloric acid to form compound (7).

An example of carboxylic acid derivatives (10) can be produced byreacting the compound (7) obtained by the procedures described abovewith a compound (8) in the presence of t-BuOK to convert the compound(7) into a compound (9), isomerizing the compound (9) withbenzenesulfinic acid, and then hydrolyzing it in the presence of analkali such as KOH and NaOH. The compound (8) mentioned above canreadily be obtained by passing through the Wittig reaction of acorresponding cyclohexanone derivative with MOTP, catalytichydrogenation in the presence of a catalyst such as Pd-C or Raney-Ni,demethylation reaction with (CH₃)₃SiI or AlCl₃, halogenation withhydrobromic acid, hydriodic acid, or the like, and reaction withtriphenylphosphine in turn.

As shown in scheme 2, an example of carboxylic acid derivatives (12) canbe produced by subjecting compound (11) and the compound (8) to theWittig reaction, isomerizing the product, and then hydrolyzing theisomerized product with an alkali.

wherein Ra has the same meaning as described above, X represents ahalogen atom, n is an integer of 0 to 2, and o is 0 or 1.

As shown in scheme 3, an example of carboxylic acid derivatives (14) canalso be produced from compound (7) in the same manner as in scheme 1with the exception that a compound (8) is replaced by a compound (13).Compound (13) can readily be obtained by preparing a Grignard reagentfrom a corresponding halide, and then passing through formylation withN-formylpiperidine or the like, reduction with sodium boron hydride orthe like, halogenation, and reaction with triphenylphosphine in turn.

As shown in scheme 4, an example of carboxylic acid derivatives (15) canalso be produced from compound (11) in the same manner as in scheme 2with the exception that a compound (8) is replaced by a compound (13).

wherein Ra has the same meaning as described above, X represents ahalogen atom, n is an integer of 0 to 2, and o is 0 or 1.

Production of alcohol derivatives:

As shown in scheme 5, compound (16) is converted into compound (17) byintroducing a protective group such as tetrahydropyranyl group and thenreacted with an organic lithium reagent such as n-butyl lithium, andiodine to convert into compound (18). Phenol derivative (19) which is anexample of the alcohol derivatives can be obtained by cyanogenating thecompound (18) and then deprotecting the cyanogenated compound.

As shown in scheme 6, phenol derivative (21) which is an example of thealcohol derivatives can also be obtained by reacting the compound (18)mentioned above with sodium trifluoroacetate/copper iodide (I) (G. E.Carr et al., Journal of the Chemical Society, Perkin Trans Reactions I,921, (1988)) or methyl fluorosulfonyldifluoroacetate/copper iodide (I)(Q, Y. Chen et al., Journal of the Chemical Society, Chemicalcommunications, 705 (1989)) to convert into compound (20), and thendeprotecting this compound.

As shown in scheme 7, the compound (17) mentioned above is reacted withan organic lithium reagent such as n-butyl lithium and phenyl lithium,and formylating agent such as N-formylpiperadine (G. A. Olah et al.,Angew. Chem., International Edition in English, 20, 878 (1981)),N-formylmorpholine (G. A. Olah et al., The Journal of Organic Chemistry,49, 385 (1984)), and DMF (G. Boss et al., Chemische Berichte, 1199(1989)) to convert into compound (22), and the compound (22) is reactedwith a fluorinating agent such as diethylaminosulfurtrifluoride (DAST)(W. J. Middleton et al., The Journal of Organic Chemistry, 40, 574(1975); S. Rozen et al., Tetrahedron Letters, 41, 111 (1985); M.Hudlicky, Organic Reactions, 35, 513 (1988); P. A. Messina et al.,Journal of Fluorine Chemistry, 42, 137 (1989)) to convert into compound(23). Phenol derivative (24) which is an example of the alcoholderivatives can also be obtained by deprotecting the compound (23).

As shown in scheme 8, the compound (22) mentioned above is reduced by areducing agent such as sodium boron hydride (SBH), lithium aluminumhydride (LAH), diisobutyl aluminum hydride (DIBAL), and sodiumbis(2-methoxyethoxy)aluminum hydride (SBMEA) to convert into compound(25), and the compound (25) is reacted with a fluorinating agent such asDAST to convert into compound (26). Phenol derivative (27) which is anexample of the alcohol derivatives can also be obtained by deprotectingthe compound (26).

As shown in scheme 9, compound (28) is treated in the presence of nitricacid and sulfuric acid to convert into compound (29) and then convertedinto xanthate by the method of Albert et al. (SyntheticCommunications_(,) 19, 547 (1989)). Phenol derivative (31) which is anexample of the alcohol derivatives can also be obtained by fluorinatingthe xanthate by the method of Kurohoshi et al., (Tetrahedron Letters,33, 29, 4173 (1992)), subjecting to a catalytic hydrogen reduction inthe presence of a platinum catalyst to convert into compound (30),reacting with hydrochloric acid and sodium nitrite, and then hydrolyzingthe resulting diazonium salt.

Further, as shown in scheme 10, the compound (29) mentioned above isfluorinated in a system of chlorodifluoromethane/sodium hydroxide (cf.WO Japanese Patent Publication (Tokuhyo) No. Hei 3-500413) and thensubjecting the product thus obtained to a catalytic hydrogen reductionin the presence of a platinum catalyst to convert into compound (32).Phenol derivative (33) which is an example of the alcohol derivativescan also be obtained by reacting the compound (32) obtained by theprocedure described above with hydrochloric acid and sodium nitrite, andthen hydrolyzing the resulting diazonium salt.

While examples of production methods are described with typicalcompounds of the present invention, it goes without saying that othercompounds of the present invention can readily be produced, forinstance, by using other known reactions in combination in addition tothe reactions used in the production methods described above.

Introduction of double bond or ester bond is sufficiently performed notonly at the final stage of the reactions but also at a selected suitabletime.

Liquid crystalline compounds of the present invention thus obtained havea wide temperature range of liquid crystal phase, low viscosity, lowthreshold voltage (V₁₀), and excellent stability, and are readily mixedwith various liquid crystal materials and good in solubility at lowtemperatures. Also, the compounds of the present invention aresufficiently stable chemically and physically under conditions in whichliquid crystal display devices are ordinarily used and thus areremarkably excellent as component of nematic liquid crystalcompositions.

Compounds of the present invention can preferably be used as componentin liquid crystal compositions for TN mode, STN mode, or TFT mode.

Compounds of the present invention having three rings exhibit a widetemperature range of liquid crystal phase and a comparatively lowviscosity, and the compounds having four rings exhibit a widertemperature range of liquid crystal phase and a particularly high phasetransition temperature to isotropic phase.

The compounds of the present invention having two or more cyclohexanerings in the molecule exhibit a low Δn and a low viscosity, and thecompounds having two or more aromatic rings exhibit an especially widetemperature range of liquid crystal phase, a particularly high phasetransition temperature to isotropic phase, and a high Δn.

Compounds of the present invention having pyridine ring, pyrimidinering, or dioxane ring exhibit a comparatively high Δε.

Since the compounds of the present invention have a large elasticconstant ratio, it is possible to make the change in transmission ofliquid crystal compositions steep and thus liquid crystal displaydevices having a high contrast can be provided by using the compounds ascomponent of liquid crystal compositions for STN.

Besides, the compounds can be modified toward more preferable ones ascomponent for STN by introducing double bond in Ra and/or Rb in theformula described above.

Compounds particularly important as chiral dopant can be provided whenthe Ra and/or Rb is an optically active group.

When the Rb is a halogen atom, halogen substituted alkyl group, orhalogen substituted alkoxy group, compounds having a high Δε; and whenthe Rb is cyano group, compounds exhibiting an especially high Δε can beprovided, respectively.

By substituting fluorine atom for the hydrogen atom in the ringstructure, the compounds can be converted into ones having a higher Δεand an improved mutual solubility.

When triple bond is introduced in Z₁, Z₂, or Z₃ in the formula describedabove, compounds exhibiting a high Δn can be obtained.

As described above, new liquid crystalline compounds having desiredphysical properties can be obtained by selecting proper rings,substituents and/or bonding groups in the compounds of the presentinvention expressed by the general formula (1). At that time, eachelement in the compounds may be selected from their isotope.

While the liquid crystal compositions provided by the present inventionmay be comprised of only a first component comprising at least oneliquid crystalline compound expressed by the general formula (1), thecompositions preferably comprise, as a second component, at least onecompound (hereinafter referred to as second component A) selected fromthe group consisting of the compounds expressed by any one of thegeneral formulas (2), (3), and (4) described above and/or at least onecompound (hereinafter referred to as second component B) selected fromthe group consisting of the compounds expressed by any one of thegeneral formulas (5), (6), (7), (8), and (9) in addition to the firstcomponent, and further, the compositions may comprise, as a thirdcomponent, a known compound for the purpose of adjusting V₁₀,temperature range of liquid crystal phase, Δn, Δε, or viscosity.

Among the second component A, compounds of the formulas (2-1) to (2-15)can be mentioned as preferable examples of the compounds included in thegeneral formula (2); compounds of the formulas (3-1) to (3-48) can bementioned as preferable examples of the compounds included in thegeneral formula (3); and compounds of the formulas (4-1) to (4-55) canbe mentioned as preferable examples of the compounds included in thegeneral formula (4), respectively.

Compounds expressed by one of the general formulas (2) to (4) exhibit apositive Δε and are excellent in heat stability and chemical stability.

Amount of the compounds to be used is suitably in the range of 1 to 99%by weight, preferably 10 to 97% by weight, and more desirably 40 to 95%by weight based on the total amount of liquid crystal composition.

Among the second component B, compounds of the formulas (5-1) to (5-24),(6-1) to (6-3), and (7-1) to (7-28) can be mentioned as preferableexamples of the compounds included in the general formula (5), (6), and(7), respectively.

Compounds expressed by one of the general formulas (5) to (7) have alarge positive Δε and are used as a component of liquid crystalcompositions particularly for the purpose of lowering V₁₀. The compoundsare also used for the purpose of adjusting viscosity, adjusting Δn, orwidening temperature range of liquid crystal phase, and further for thepurpose of improving th steepness.

Among the second component B, the compounds of the formula (8-1) to(8-8), and (9-1) to (9-13) can be mentioned as preferable examples ofthe compounds included in the general formula (8) or (9).

Compounds expressed by the general formula (8) or (9) have a negative ora small positive Δε value. Among them, the compounds expressed by thegeneral formula (8) are used as a component of liquid crystalcompositions principally for the purpose of reducing viscosity andadjusting Δn, and the compounds expressed by the general formula (9) areused for the purpose of widening temperature range of liquid crystalphase and/or for the purpose of adjusting Δn.

Compounds expressed by one of the general formulas (5) to (9) areindispensable particularly when liquid crystal compositions for STNdisplay mode or ordinary TN display mode are produced. Amount of thecompounds to be used is suitably in the range of 1 to 99% by weight,preferably 10 to 97% by weight, and 40 to 95% by weight based on thetotal amount of liquid crystal composition when liquid crystalcompositions for ordinary STN display mode or TN display mode areproduced.

Liquid crystal compositions provided according to the present inventionpreferably comprise at least one liquid crystalline compound expressedby the general formula (1) in the ratio of 0.1 to 99% by weight todevelop excellent properties.

The liquid crystal compositions are usually produced by methods whichare known by themselves, for instance, by a method in which variouscomponents are dissolved each other at a high temperature. Moreover, theliquid crystal compositions are improved and optimized depending onintended uses by adding a suitable additive, when necessary. Such anadditive is well known in the art and described in detail in theliterature. Usually, a chiral dopant or the like is added to induce ahelical structure of liquid crystals thereby adjust a required twistingangle and avoid a reverse-twist. As its examples, optically activecompounds expressed by one of the following formulas (Op-1) to (Op-8)can be mentioned.

Liquid crystal compositions of the present invention can be used as onesfor GH (guest-host) mode by adding a dichroic dye such as merocyaninetype, styryl type, azo type, azomethine type, azoxy type, quinophthalonetype, anthraquinone type, or tetrazine type dye. Liquid crystalcompositions of the present invention can also be used as liquid crystalcompositions for NCAP which is prepared by the microencapsulation of anematic liquid crystal, or for polymer dispersed liquid crystal displaydevices (PDLCD) which are prepared by forming in the liquid crystal athree-dimesnsional network structure of a polymer, for example, polymernetwork liquid crystal display devices (PNLCD) as well as forelectrically controlled birefringence (ECB) mode or dynamic scattering(DS) mode.

Liquid crystal compositions of the present invention are produced by themethods as described above, and the following Composition Examples 1through 33 can be shown as examples of the compositions.

In the composition examples, compounds are designated by theabbreviation according to the definitions shown in the followingTable 1. Specifically, left hand side terminal group is indicated by n-,nO-, Vn-, nVm-, or nVmVk- (n, m, and k are an integer of 1 or more);bonding group is indicated by 2, E, T, V, or CF20; ring structure isindicated by B, B(F), B(F,F), H, Py, D, or Ch; right hand side terminalgroup is indicated by —F, —CL, —C, —CF3, —OCF3, —OCF2H, -n, -On, or -Eme(n is an integer of 1 or more). Number of compound affixed to thecompounds of the present invention is the same as that shown in Examplesbelow.

TABLE 1 Left side terminal group Symbol Bonding group SymbolC_(n)H_(2n+1)— n— —CH₂CH₂— 2 C_(n)H₂₊₁O— nO— —COO— EC_(n)H_(2n+1)C_(m)H_(2m)— nOm— —C≡C— T CH₂═CHC_(n)H_(2n)— Vn— —CH═CH— VC_(n)H_(2n+1)CH₂═CHC_(m)H_(2m)— nVm— —CF₂O— CF2OC_(n)H_(2n+1)CH₂═CHC_(m)H_(2m)CH═ nVmVk— CHC_(k)H_(2k)— Right sideterminal Ring structure Symbol group Symbol

B —F— —Cl— —F —CL

B(F) —CN —CF₃ —C —CF3

B(F, F) —OCF₃ —OCF₂H —OCF3 —OCF2H

H —C_(n)H_(2n+1) —OCnH2n+1 —n —On

Py —COOCH₃ —EMe

D

Ch Composition Example 1 3-HVBEB(F, F)—C (No. 1) 10.0% by weight5-HVHEB(F, F)—C (No. 60) 10.0% by weight 3-HVB(F, F)EB(F, F)—C (No. 23)10.0% by weight 5-HVHEB-5 (No. 74) 15.0% by weight V-HVHEH-3 (No. 97)15.0% by weight 5-HVHEB(F)—OCF3 (No. 51) 10.0% by weight 3-HVB(F,F)EB(F, F)—CF3 (No. 25) 10.0% by weight 3-HVB(F, F)EB(F)—OCF3 (No. 20)10.0% by weight 3-HVBEB(F, F)—CF3 (No. 13) 10.0% by weight CompositionExample 2 5-HVHEB-5 (No. 74) 10.0% by weight 5-HVHEB(F)—OCF3 (No. 51)15.0% by weight 3-HVB(F, F)EB(F, F)—CF3 (No. 25) 10.0% by weight3-HVB(F, F)EB(F)—OCF3 (No. 20) 10.0% by weight 3-HVBEB(F, F)—CF3 (No.13) 15.0% by weight 3-HVBEB(F)—CF3 (No. 6) 10.0% by weight 3-HVBEB(F,F)—OCF3 (No. 14) 10.0% by weight 3-HVBEB(F, F)—OCF2H (No. 15) 10.0% byweight 5-HVHEB(F)—CF2H (No. 58) 10.0% by weight Composition Example 35-HVHEB-5 (No. 74) 5.0% by weight V2-HB—C 10.0% by weight 1V2-HB—C 10.0%by weight 3-HB—C 26.0% by weight 5-HB—C 12.0 % by weight 3-HB(F)—C 8.0%by weight 2-BEB—C 3.0% by weight V2-HHB-1 3.0% by weight 3-HHB—O1 4.0%by weight 3-HHB-3 10.0% by weight 3-H2BTB-2 3.0% by weight 3-H2BTB-33.0% by weight 3-H2BTB-4 3.0% by weight Composition Example 4 3-HVBEB(F,F)—C (No. 1) 10.0% by weight 3-HVHEB(F, F)—C (No. 60) 5.0% by weight3-HVB(F, F)EB(F, F)—C (No. 23) 5.0% by weight 1V2-BEB(F, F)—C 11.0% byweight 2O1-BEB(F)—C 5.0% by weight 3O1-BEB(F)—C 9.0% by weight 3-HB(F)—C15.0% by weight 3-HH-4 5.0% by weight 1O1-HH-3 3.0% by weight 4-BTB—O25.0% by weight 2-HHB(F)—C 3.0% by weight 3-HHB(F)—C 4.0% by weight3-H2BTB-2 4.0% by weight 3-H2BTB-3 4.0% by weight 3-H2BTB-4 4.0% byweight 2-BTB-1 1.0% by weight 1-BTB-6 2.0% by weight 4-BTB-4 1.0% byweight 3-HH-2V 2.0% by weight 4-HH—V 2.0% by weight Composition Example5 V-HVHEH-3 (No. 97) 3.0% by weight 5-HVHEB-5 (No. 74) 5.0% by weight2-BB—C 6.0% by weight 2O2O—BB—C 3.0% by weight 1O1-HB—C 10.0% by weight2O1-HB—C 7.0% by weight 2-BEB—C 12.0% by weight 5-PyB—F 8.0% by weight2-PyB-2 2.0% by weight 3-PyB-2 2.0% by weight 4-PyB-2 2.0% by weightV—HHB-1 5.0% by weight 3-HHB-1 7.0% by weight 3-HHB-3 10.0% by weight2-PyBH-3 5.0% by weight 3-PyBH-3 3.0% by weight 4-PyBH-3 3.0% by weight3-PyBB—F 2.0% by weight 4-PyBB—F 2.0% by weight 6-PyBB-2 3.0% by weightComposition Example 6 3-HVBEB(F, F)—C (No. 1) 3.0% by weight 5-HVHEB-5(No. 74) 3.0% by weight 3-PyB(F)—F 6.0% by weight 2-BEB—C 12.0% byweight 3-BEB—C 4.0% by weight 3-DB—C 10.0% by weight 4-DB—C 10.0% byweight 3-HEB—O4 8.0% by weight 4-HEB—O2 6.0% by weight 5-HEB—O1 6.0% byweight 3-HEB—O2 5.0% by weight 5-HEB—O2 4.0% by weight 3-HHB-1 3.0% byweight 3-HHEBB—C 3.0% by weight 5-HBEBB—C 3.0% by weight 1O—BEB-2 4.0%by weight 4-HEB-3 4.0% by weight 5-HEB-1 4.0% by weight 6-PyB—O2 2.0% byweight Composition Example 7 5-HVHEB(F, F)—C (No. 60) 3.0% by weight3-HB—C 20.0% by weight 3-HHB-1 7.0% by weight 3-HHB-3 8.0% by weight5-HEB—F 2.5% by weight 7-HEB—F 2.5% by weight 3-HHEB—F 1.0% by weight5-HHEB—F 1.0% by weight 3-HEB—O4 4.0% by weight 4-HEB—O2 3.0% by weight5-HEB—O1 3.0% by weight 3-HEB—O2 2.5% by weight 5-HEB—O2 2.0% by weight3-HB(F)TB-2 6.0% by weight 3-HB(F)TB-3 5.0% by weight 3-HB(F)—VB-4 5.0%by weight 3-H2BTB-2 4.0% by weight 3-H2BTB-3 4.0% by weight 3-H2BTB-44.0% by weight 3-HHEBB—C 3.0% by weight 3-HBEBB—C 3.0% by weight5-HBEBB—C 3.0% by weight 3-HH—COOMe 1.5% by weight 1O1-HBBH-3 2.0% byweight Composition Example 8 5-HVHEB(F, F)—C (No. 60) 5.0% by weight5-PyB(F)—F 13.0% by weight 2-HB(F)—C 10.0% by weight 3-HB(F)—C 12.0% byweight 3O—BB—C 8.0% by weight 2-HHB—C 6.0% by weight 3-HHB—C 6.0% byweight 4-HHB—C 6.0.% by weight 5-HHB—C 6.0% by weight 2-HHB(F)—C 5.0% byweight 3-HHB(F)—C 5.0% by weight 3-PyBB—F 7.0% by weight 4-PyBB—F 6.0%by weight 5-HBB—C 2.0% by weight 3-HB(F)EB(F)—C 3.0% by weightComposition Example 9 5-HVHEB(F)—OCF3 (No. 51) 12.0% by weight 3-HVB(F,F)EB(F)—OCF3 (No. 20) 8.0% by weight 3-HVBEB(F)—CF3 (No. 6) 8.0% byweight 5-HVHEB(F)—CF2H (No. 58) 8.0% by weight 5-H2B(F)—F 4.0% by weight7-HB(F)—F 10.0% by weight 2-HHB(F)—F 5.0% by weight 3-HHB(F)—F 5.0% byweight 5-HHB(F)—F 5.0% by weight 2-H2HB(F)—F 8.0% by weight 3-H2HB(F)—F4.0% by weight 5-H2HB(F)—F 8.0% by weight 2-HBB(F)—F 2.5% by weight3-HBB(F)—F 2.5% by weight 5-HBB(F)—F 5.0% by weight 3-HHB—F 5.0% byweight Composition Example 10 3-HVB(F, F)EB(F, F)—CF3 (No. 25) 5.0% byweight 3-HVBEB(F, F)—OCF3 (No. 14) 5.0% by weight 3-HVBEB(F, F)—OCF2H(No. 15) 5.0% by weight 7-HB(F, F)—F 5.0% by weight 3-HBB(F, F)—F 4.0%by weight 5-HBB(F, F)—F 4.0% by weight 3-HHB(F, F)—F 7.0% by weight5-HHB(F, F)—F 5.0% by weight 3-HH2B(F, F)—F 5.0% by weight 5-HH2B(F,F)—F 5.0% by weight 3-H2HB(F, F)—F 9.0% by weight 4-H2HB(F, F)—F 9.0% byweight 5-H2HB(F, F)—F 9.0% by weight 3-HHEB(F, F)—F 9.0% by weight4-HHEB(F, F)—F 3.0% by weight 5-HHEB(F, F)—F 3.0% by weight 3-HBEB(F,F)—F 2.0% by weight 5-HBEB(F, F)—F 2.0% by weight 3-HHHB(F, F)—F 2.0%byweight 5-HH2BB(F, F)—F 2.0% by weight Composition Example 115-HVHEB(F)—OCF3 (No. 51) 6.0% by weight 3-HVBEB(F, F)—CF3 (No. 13) 5.0%by weight 7-HB(F, F)—F 5.0% by weight 2-HHB(F) F 10.0% by weight3-HHB(F)—F 10.0% by weight 5-HHB(F)—F 10.0% by weight 3-HHB-OCF3 3.0% byweight 5-HHB-OCF3 3.0% by weight 2-H2HB(F)—F 4.0% by weight 3-H2HB(F)—F2.0% by weight 5-H2HB(F)—F 4.0% by weight 3-HHB(F, F)—F 8.0% by weight4-HHB(F, F)—F 4.0% by weight 3-H2HB(F, F)—F 5.0% by weight 4-H2HB(F,F)—F 4.0% by weight 5-H2HB(F, F)—F 4.0% by weight 3-HH2B(F, F)—F 5.0% byweight 5-HH2B(F, F)—F 5.0% by weight 3-HH2B-OCF3 3.0% by weightComposition Example 12 5-HVHEB(F)—OCF3 (No. 51) 10.0% by weight5-HVHEB-5 (No. 74) 6.0% by weight 3-HVB(F, F)EB(F)—OCF3 (No. 20) 5.0% byweight 5-HB—F 5.0% by weight 7-HB(F)—F 5.0% by weight 2-HHB(F)—F 10.0%byweight 3-HHB(F)—F 10.0% by weight 5-HHB(F)—F 10.0% by weight 3-HB—O210.0% by weight 3-HHB—F 4.0% by weight 3-HHB-1 3.0% by weight 3-HHB-33.0% by weight 2-HBB—F 6.0% by weight 3-HBB—F 5.0% by weight 3-HHEB—F2.0% by weight 5-HHEB—F 2.0% by weight 3-HBEB—F 2.0% by weight 3-HHEBB—F2.0% by weight Composition Example 13 5-HVHEB(F)—OCF3 (No. 51) 5.0% byweight 3-HVB(F, F)EB(F, F)—CF3 (No. 25) 3.0% by weight 3-HVBEB(F, F)—CF3(No. 13) 2.0% by weight 7-HB(F, F)—F 7.0% by weight 3-HB—CL 4.0% byweight 5-HB—CL 3.0% by weight 7-HB—CL 3.0% by weight 2-BTB—O1 12.0% byweight 2-HBB(F)—F 2.5% by weight 3-HBB(F)—F 2.5% by weight 5-HBB(F)—F5.0% by weight 5-HBB(F, F)—F 5.0% by weight 2-HBB—CL 5.0% by weight3-HBB—CL 5.0% by weight 3-HB(F)TB-2 6.0% by weight 3-HB(F)TB-3 6.0% byweight 3-HB(F)TB-4 6.0% by weight 3-H2BTB-2 4.0% by weight 3-H2BTB-34.0% by weight 3-H2HB(F)—CL 3.0% by weight 5-H2HB(F)—CL 2.0% by weight3-H2BB(F, F)—F 5.0% by weight Composition Example 14 4-HVHEB(F)—OCF3(No. 51) 10.0% by weight 5-HVHEB(F)—CF2H (No. 58) 10.0% by weight5-HVHEB-5 (No. 74) 5.0% by weight 5-HB—F 10.0% by weight 6-HB—F 5.0% byweight 7-HB—F 5.0% by weight 2-HHB—OCF3 5.0% by weight 3-HHB—OCF3 5.0%by weight 5-HHB—OCF3 5.0% by weight 3-HH2B—OCF3 6.0% by weight5-HH2B—OCF3 6.0% by weight 3-HB(F)B-3 4.0% by weight 5-HB(F)B-3 4.0% byweight 2-HBB(F)—F 5.0% by weight 3-HBB(F)—F 5.0% by weight 5-HBB(F)—F10.0% by weight Composition Example 15 3-HVB(F, F)EB(F, F)—CF3 (No. 25)6.0% by weight 3-HVBEB(F, F)—OCF2H (No. 15) 6.0% by weight 5-HB—F 3.0%by weight 6-HB—F 3.0% by weight 7-HB—F 3.0% by weight 3-HHB—OCHF2 4.0%by weight 5-HHB—OCHF2 4.0% by weight 3-HHB(F, F)—OCF2H 9.0% by weight5-HHB(F, F)—OCF2H 9.0% by weight 2-HHB—OCF3 6.0% by weight 3-HHB—OCF36.0% by weight 4-HHB—OCF3 6.0% by weight 5-HHB—OCF3 6.0% by weight3-HH2B(F)—F 10.0% by weight 5-HH2B(F)—F 10.0% by weight 3-HHEB(F)—F 4.0%by weight 5-HHEB(F)—F 5.0% by weight Composition Example 16 3-HVBEB(F,F)—C (No. 1) 4.0% by weight 5-HVHEB(F, F)—C (No. 60) 4.0% by weight5-HVHEB-5 (No. 74) 5.0% by weight 4-HHEB(F)—F 5.0% by weight 5-HHEB(F)—F5.0% by weight 2-BEB(F)—C 5.0% by weight 3-BEB(F)—C 7.0% by weight4-BEB(F)—C 5.0% by weight 5-BEB(F)—C 7.0% by weight 1O3-HB(F)—C 11.0% byweight 3-HHEB(F)—F 5.0% by weight 5-HHEB(F)—F 5.0% by weight 2-HBEB(F)—C3.0% by weight 3-HBEB(F)—C 3.0% by weight 4-HBEB(F)—C 3.0% by weight5-HBEB(F)—C 3.0% by weight 3-HBTB-2 5.0% by weight V2-HH-3 10.0% byweight V2-HHB-1 5.0% by weight Composition Example 17 3-HVBEB(F, F)—C(No. 1) 5.0% by weight 3-HVB(F, F)EB(F, F)—C (No. 23) 5.0% by weight1V2-BEB(F, F)—C 5.0% by weight 3-HB—C 15.0% by weight 1-BTB-3 5.0% byweight 2-BTB-1 10.0% by weight 3-HH-4 11.0% by weight 3-HHB-1 11.0% byweight 3-HHB-3 9.0% by weight 3-H2BTB-2 4.0% by weight 3-H2BTB-3 4.0% byweight 3-H2BTB-4 4.0% by weight 3-HB(F)TB-2 6.0% by weight 3-HB(F)TB-36.0% by weight Composition Example 18 5-HVHEB(F, F)—C (No. 60) 5.0% byweight 3O1-BEB(F)—C 15.0% by weight 4O1-BEB(F)—C 13.0% by weight5O1-BEB(F)—C 13.0% by weight 2-HHB(F)—C 15.0% by weight 3-HHB(F)—C 15.0%by weight 3-HB(F)TB-2 4.0% by weight 3-HB(F)TB-3 4.0% by weight3-HB(F)TB-4 4.0% by weight 3-HHB-1 8.0% by weight 3-HHB—O1 4.0% byweight Composition Example 19 5-HVHEB-5 (No. 74) 6.0% by weight 5-PyB—F4.0% by weight 3-PyB(F)—F 4.0% by weight 2-BB—C 5.0% by weight 4-BB—C4.0% by weight 5-BB—C 5.0% by weight 2-PyB-2 2.0% by weight 3-PyB-2 2.0%by weight 4-PyB-2 2.0% by weight 6-PyB—O5 3.0% by weight 6-PyB—O6 3.0%by weight 6-PyB—O7 3.0% by weight 6-PyB—O8 3.0% by weight 3-PyBB—F 6.0%by weight 4-PYBB—F 6.0% by weight 5-PyBB—F 6.0% by weight 3-HHB-3 8.0%by weight 2-H2BTB-2 4.0% by weight 2-H2BTB-3 4.0% by weight 2-H2BTB-45.0% by weight 3-H2BTB-2 5.0% by weight 3-H2BTB-3 5.0% by weight3-H2BTB-4 5.0% by weight Composition Example 20 3-HVBEB(F, F)—C (No. 1)3.0% by weight 5-HVHEB-5 (No. 74) 3.0% by weight 3-DB—C 10.0% by weight4-DB—C 10.0% by weight 2-BEB—C 12.0% by weight 3-BEB—C 4.0% by weight3-PyB(F)—F 6.0% by weight 3-HEB—O4 8.0% by weight 4-HEB—O2 6.0% byweight 5-HEB—O1 6.0% by weight 3-HEB—O2 5.0% by weight 5-HEB—O2 4.0% byweight 5-HEB-5 5.0% by weight 4-HEB-5 5.0% by weight 1O—BEB-2 4.0% byweight 3-HHB-1 3.0% by weight 3-HHEBB—C 3.0% by weight 3-HBEBB—C 3.0% byweight Composition Example 21 3-HVB(F, F)EB(F, F)—C (No. 23) 3.0% byweight 3-HB—C 15.0% by weight 7-HB—C 3.0% by weight 1O1-HB—C 10.0% byweight 3-HB(F)—C 10.0% by weight 2-PyB-2 2.0% by weight 3-PyB-2 2.0% byweight 4-PyB-2 2.0% by weight 1O1-HH-3 7.0% by weight 2-BTB—O1 7.0% byweight 3-HHB-1 7.0% by weight 3-HHB—F 4.0% by weight 3-HHB—O1 4.0% byweight 3-HHB-3 8.0% by weight 3-H2BTB-2 3.0% by weight 3-H2BTB-3 3.0% byweight 2-PyBH-3 4.0% by weight 3-PyBH-3 3.0% by weight 3-PyBB-2 3.0% byweight Composition Example 22 3-HVB(F, F)EB(F, F)—C (No. 23) 5.0% byweight 3-HVBEB(F, F)—C (No. 1) 12.0% by weight 5-HVHEB-5 (No. 74) 3.0%by weight 5O1-BEB(F)—C 4.0% by weight 1V2-BEB(F, F)—C 10.0% by weight3-HH—EMe 10.0% by weight 3-HB—O2 18.0% by weight 7-HEB—F 2.0% by weight3-HHEB—F 2.0% by weight 5-HHEB—F 2.0% by weight 3-HBEB—F 4.0% by weight2O1-HBEB(F)—C 2.0% by weight 3-HB(F)EB(F)—C 2.0% by weight 3-HBEB(F,F)—C 2.0% by weight 3-HHB—F 4.0% by weight 3-HHB—O1 4.0% by weight3-HHB-3 10.0% by weight 3-HEBEB—F 2.0% by weight 3-HEBEB-1 2.0% byweight Composition Example 23 5-HVHEB(F, F)—C (No. 60) 2.0% by weight2O1-BEB(F)—C 3.0% by weight 3O1-BEB(F)—C 12.0% by weight 5O1-BEB(F)—C4.0% by weight 1V2-BEB(F, F)—C 16.0% by weight 3-HB—O2 10.0% by weight3-HH-4 3.0% by weight 3-HHB—F 3.0% by weight 3-HHB-1 8.0% by weight3-HHB—O1 4.0% by weight 3-HBEB—F 4.0% by weight 3-HHEB—F 7.0% by weight5-HHEB—F 7.0% by weight 3-H2BTB-2 4.0% by weight 3-H2BTB-3 4.0% byweight 3-H2BTB-4 4.0% by weight 3-HB(F)TB-2 5.0% by weight CompositionExample 24 3-HVB(F, F)EB(F, F)—C (No. 23) 10.0% by weight 2-BEB—C 12.0%by weight 3-BEB—C 4.0% by weight 4-BEB—C 6.0% by weight 3-HB—C 18.0% byweight 3-HEB—O4 12.0% by weight 4-HEB—O2 8.0% by weight 5-HEB—O1 8.0% byweight 3-HEB—O2 6.0% by weight 5-HEB—O2 5.0% by weight 3-HHB-1 7.0% byweight 3-HHB—O1 4.0% by weight Composition Example 25 5-HVHEB(F)—OCF3(No. 51) 2.0% by weight 5-HVHEB-5 (No. 74) 2.0% by weight 2-BEB—C 10.0%by weight 5-BB—C 10.0% by weight 7-BB—C 7.0% by weight 1-BTB-3 7.0% byweight 2-BTB-1 10.0% by weight 1O—BEB-2 10.0% by weight 1O—BEB-5 12.0%by weight 2-HHB-1 4.0% by weight 3-HHB—F 4.0% by weight 3-HHB-1 5.0% byweight 3-HHB—O1 4.0% by weight 3-HHB-3 13.0% by weight CompositionExample 26 5-HVHEB(F, F)—C (No. 60) 2.0% by weight 5-HVHEB-5 (No. 74)2.0% by weight 2-HB—C 5.0% by weight 3-HB—C 10.0% by weight 3-HB—O215.0% by weight 2-BTB-1 3.0% by weight 3-HHB-1 8.0% by weight 3-HHB—F4.0% by weight 3-HHB—O1 5.0% by weight 3-HHB-3 12.0% by weight 3-HHEB—F4.0% by weight 5-HHEB—F 4.0% by weight 2-HHB(F)—F 7.0% by weight3-HHB(F)—F 7.0% by weight 5-HHB(F)—F 7.0% by weight 3-HHB(F, F)—F 5.0%by weight Composition Example 27 3-HVBEB(F, F)—C (No. 1) 10.0% by weight5-HVHEB(F, F)—C (No. 60) 3.0% by weight 2-HHB(F)—F 17.0% by weight3-HHB(F)—F 17.0% by weight 5-HHB(F)—F 16.0% by weight 2-H2HB(F)—F 10.0%by weight 3-H2HB(F)—F 5.0% by weight 5-H2HB(F)—F 10.0% by weight2-HBB(F)—F 6.0% by weight 3-HBB(F)—F 6.0% by weight Composition Example28 3-HVBEB(F, F)—C (No. 1) 8.0% by weight 3-HVB(F, F)EB(F, F)—C (No. 23)8.0% by weight 7-HB(F, F)—F 3.0% by weight 3-HB—O2 7.0% by weight2-HHB(F)—F 10.0% by weight 3-HHB(F)—F 10.0% by weight 5-HHB(F)—F 10.0%by weight 2-HBB(F)—F 9.0% by weight 3-HBB(F)—F 9.0% by weight 2-HBB—F4.0% by weight 3-HBB—F 4.0% by weight 5-HBB—F 3.0% by weight 3-HBB(F,F)—F 5.0% by weight 5-HBB(F, F)—F 10.0% by weight Composition Example 293-HVBEB(F, F)—C (No. 1) 6.0% by weight 3-HB—CL 10.0% by weight 5-HB—CL4.0% by weight 7-HB—CL 4.0% by weight 1O1-HH-5 5.0% by weight 2-HBB(F)—F8.0% by weight 3-HBB(F)—F 8.0% by weight 5-HBB(F)—F 8.0% by weight4-HHB—CL 8.0% by weight 5-HHB—CL 8.0% by weight 3-H2HB(F)—CL 4.0% byweight 3-HBB(F, F)—F 10.0% by weight 5-H2BB(F, F)—F 9.0% by weight3-HB(F)VB-2 4.0% by weight 3-HB(F)VB-3 4.0% by weight CompositionExample 30 5-HVHEB(F, F)—C (No. 60) 3.0% by weight 3-HHB(F, F)—F 6.0% byweight 3-H2HB(F, F)—F 8.0% by weight 4-H2HB(F, F)—F 8.0% by weight5-H2HB(F, F)—F 8.0% by weight 3-HBB(F, F)—F 21.0% by weight 5-HBB(F,F)—F 20.0% by weight 3-H2BB(F, F)—F 10.0% by weight 5-HHBB(F, F)—F 3.0%by weight 5-HHEBB—F 2.0% by weight 3-HH2BB(F, F)—F 3.0% by weight1O1-HBBH-4 4.0% by weight 1O1-HBBH-5 4.0% by weight Composition Example31 3-HVB(F, F)EB(F, F)—C (No. 23) 10.0% by weight 5-HB—F 12.0% by weight6-HB—F 9.0% by weight 7-HB—F 7.0% by weight 2-HHB—OCF3 7.0% by weight3-HHB—OCF3 7.0% by weight 4-HHB—OCF3 7.0% by weight 5-HHB—OCF3 5.0% byweight 3-HH2B—OCF3 4.0% by weight 5-HH2B—OCF3 4.0% by weight 3-HHB(F,F)—OCF3 5.0% by weight 3-HBB(F)—F 10.0% by weight 3-HH2B(F)—F 3.0% byweight 3-HB(F)BH-3 3.0% by weight 5-HBBH-3 3.0% by weight 3-HHB(F,F)—OCF2H 4.0% by weight Composition Example 32 5-HVHEB(F, F)—C (No. 60)3.0% by weight 3-BEB(F)—C 8.0% by weight 3-HB—C 5.0% by weight V—HB—C8.0% by weight 1V—HB—C 8.0% by weight 3-HH-2 3.0% by weight 3-HH-2V14.0% by weight 3-HH-2V1 7.0% by weight V2-HHB-1 15.0% by weight 3-HHB-15.0% by weight 3-HHEB—F 7.0% by weight 3-H2BTB-2 6.0% by weight3-H2BTB-3 6.0% by weight 3-H2BTB-4 5.0% by weight Composition Example 335-HVHEB-5 (No. 74) 5.0% by weight 3-H2HB(F, F)—F 7.0% by weight5-H2HB(F, F)—F 8.0% by weight 3-HHB(F, F)—F 10.0% by weight 3-HH2B(F,F)—F 9.0% by weight 5-HH2B(F, F)—F 9.0% by weight 3-HBB(F, F)—F 15.0% byweight 5-HBB(F, F)—F 15.0% by weight 3-HBEB(F, F)—F 2.0% by weight4-HBEB(F, F)—F 2.0% by weight 5-HBEB(F, F)—F 2.0% by weight 3-HHEB(F,F)—F 10.0% by weight 4-HHEB(F, F)—F 3.0% by weight 5-HHEB(F, F)—F 3.0%by weight

BEST MODE FOR CARRYING OUT THE INVENTION

Now, the present invention will be described in more detail withreference to Examples. In each of the Examples, Cr indicates crystal;S_(A), smectic phase A; S_(B), smectic phase B; S_(x), smectic phasestructure of which has not yet be analyzed; N, nematic phase; and Iso,isotropic phase, and the unit of all phase transition temperatures is °C.

EXAMPLE 1

Preparation of (E)-3,5-difluoro-4-cyanophenyl4-(2-(trans-4-propylcyclohexyl)vinyl)benzoate (Compound expressed by thegeneral formula (1) wherein Ra is C₃H₇, Rb is cyano group, m is 0, A₁ istrans-1,4-cyclohexylene group, A₂ is 1,4-phenylene group, A₃ is3,5-difluoro-1,4-phenylene group, Z₁ is —CH═CH—, and Z₂ is —COO—;Compound No. 1)

First Step

Preparation of (E)-4-(2-(trans-4-propylcyclohexyl)vinyl)benzoic acid

To a mixture of 25.0 g (0.11 mol) oftrans-4-propylcyclohexylmethyltriphenylphosphonium bromide and 100 ml oftetrahydrofuran (THF) was added 12.2 g (0.10 mol) of t-BuOK whilemaintaining a temperature of lower than −20° C., and stirred for 1 hour.Subsequently, 70 ml of solution of 12.9 g (0.10 mol) of4-cyanobenzaldehyde in THF was added dropwise to the solution whilemaintaining a temperature of lower than −20° C., and stirred at the sametemperature for 2 hours to react. After finishing of the reaction, 50 mlof water was added to the reaction product and then extracted with 100ml of toluene. The organic layer thus obtained was washed with waterthrice and then dried over anhydrous magnesium sulfate. The solvent wasdistilled off under a reduced pressure, and the residue was subjected tosilica gel column chromatography (eluent: toluene) to obtain 12.1 g of acrude 4-(2-(trans-4-propylcyclohexyl)vinyl)benzonitrile.

This nitrile in an amount of 11.7 g (0.05 ml) was added to a mixture of13.9 g (0.07 ml) of dihydrated sodium benzenesufinate, 12 ml of 6N-HCl,and 70 ml of ethanol, and reacted under reflux for 4 hours. Afterfinishing of the reaction, 50 ml of water was added to the reactionproduct and then extracted with 150 ml of toluene. The organic layerthus obtained was washed with saturated aqueous sodium carbonatesolution thrice and with water thrice, and then dried over anhydrousmagnesium sulfate. The solvent was distilled off under a reducedpressure, and the residue was subjected to silica gel columnchromatography (eluent: toluene) to obtain 12.0 g of a crude(E)-4-(2-(trans-4-propylcyclohexyl)vinyl)benzonitrile.

This crude product in an amount of 10.0 g (0.04 mol) was added to amixture of 11.1 g (0.20 mol) of potassium hydroxide, 40 ml of water, and250 ml of ethylene glycol, and reacted while being stirred at 140° C.for 25 hours. After finishing of the reaction, the reaction product waspoured into 600 ml of 6N-HCL, and then extracted with 500 ml of diethylether twice. The organic layer thus obtained was washed with water fivetimes and then dried over anhydrous magnesium sulfate. The solvent wasdistilled off under a reduced pressure, and the residue wasrecrystallized from a mixed solvent of toluene/heptane to obtain 5.7 gof (E)-4-(2-(trans-4-propylcyclohexyl)vinyl)benzoic acid (yield 53.4%).

Second Step

This product in an amount of 1.6 g (5.9 mmol) was mixed with 1.0 g (6.2mmol) of 3,5-difluoro-4-cyanophenol, 0.2 g (1.8 mmol) of DMAP, and 25 mlof dichloromethane. To this mixture was added dropwise 7 ml of solutionof 1.6 g (7.6 mmol) of DCC in dichloromethane while being cooled withice in 5 min, stirred as it was for 12 hours, and then separatedcrystals were filtered off.

To the filtrate thus obtained was added 50 ml of toluene. This solutionwas washed with 2N-NaOH five times and with water thrice, and then driedover anhydrous magnesium sulfate. The solvent was distilled off under areduced pressure, and the residue thus obtained was subjected to silicagel column chromatography (eluent: toluene) to obtain 2.0 g of a crude(E)-3,5-difluoro-4-cyanophenyl4-(2-(trans-4-propylcyclohexyl)vinyl)benzoate. This crude product wasrecrystallized from a mixed solvent of heptane/diethyl ether to obtain1.3 g of the subjective compound (yield 57.1%).

This compound exhibited liquid crystal phase and its phase transitiontemperatures were as follows:

C 76.9˜78.1 N 210.8˜210.9 Iso

Further, mass spectrum data of this compound well supported itsstructure.

Mass spectrometry: 409 (M⁺); H¹NMR (CDCl₃, TMS internal standard); δ(ppm); 0.89-1.89 (m, 17H); 6.47 (m, 2H); 7.05 (brd, 2H); 7.46 (d, 2H);8.06 (d, 2H).

This compound (Compound No. 1) is similar to Compound (a) described inthe Laid-open Japanese Patent Publication No. Hei 4-279560 mentionedabove in their structure since Compound No. 1 is the same as Compound(a) with the exception that the covalent bond of bonding group isreplaced by alkenylene group. However, they are considerably differentin their properties (phase transition temperatures).

That is, whereas the phase transition temperatures of Compound No. 1were as described above, those of Compound (a) are

C 89.8 N 140.9 Iso (cf. Laid-open Japanese Patent Publication No. Hei4-279560), and it can be understood that the former is wider intemperature range of liquid crystal phase by about 80° C. and higher inNI about 70° C. than the latter.

According the methods of Example 1, the following compounds (CompoundsNo. 2 to No. 50) are prepared:

No.  2

 3

 4

 5

 6

 7

 8

 9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

C 76.5-77.4 N 177.5-177.6 Iso 24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

EXAMPLE 2

Preparation of (E)-3-fluoro-4-trifluoromethoxyphenyltrans-4-(2-(trans-4-pentylcyclohexyl)vinyl)cyclohexanecarboxylate(Compound expressed by the general formula (1) wherein Ra is C₅H₁₁, Rbis OCF₃, m is 0, both A₁ and A₂ are trans-1,4-cyclohexylene group, A₃ is3-fluoro-1,4-phenylene group, Z₁ is —CH═CH—, and Z₂ is —COO—; CompoundNo. 51)

The (E)-trans-4-(2-(trans-4-pentylcyclohexyl)vinyl)cyclohexanecarboxylicacid, which was prepared by the same manner as in the first step ofExample 1 with the exception that ethyltrans-4-formylcyclohexanecarboxylate was used in place of4-cyanobenzaldehyde, in an amount of 1.1 g (3.6 mmol) was mixed with 0.8g (3.9 mmol) of 3-fluoro-4-trifluromethoxyphenol, 0.1 g (1.1 mmol) ofDMAP, and 20 ml of dichloromethane. To this mixture was added dropwise 4ml of solution of 1.0 g (4.7 mmol) of DCC in dichloromethane while beingcooled with ice in 5 min, and stirred as it was for 12 hours. Separatedcrystals were filtered off, 70 ml of toluene was added to the filtrate,and the filtrate was washed with 2N-NaOH five times and with waterthrice, and then dried over anhydrous magnesium sulfate. The solvent wasdistilled off under a reduced pressure. The residue thus obtained wassubjected to silica gel column chromatography (eluent:toluene) to obtain1.7 g of a crude (E)-3-fluoro-4-trifluoromethoxyphenyltrans-4-(2-(trans-4-pentylcyclohexyl)vinyl)cyclohexanecarboxylate. Thiscrude product was recrystallized from a mixed solvent of heptane/diethylether to obtain 0.7 g of the subjective compound (yield 38.7%).

This compound exhibited liquid crystal phase and its phase transitiontemperatures were as follows:

C 78.3˜78.9 N 161.8˜161.9 Iso

Further, mass spectrum data of this compound well supported itsstructure.

Mass spectrometry: 484 (M⁺); H¹NMR (CDCl₃, TMS internal standard); δ(ppm); 0.88-2.47 (m, 31H); 5.33 (m, 2H); 6.85-7.40 (m, 3H).

According the methods of Example 2, the following compounds (CompoundsNo. 52 to No. 73) are prepared.

No. 52

53

54

55

56

57

58

59

60

C 81.6-82.1 N 166.5- 166.6 Iso 61

62

63

64

65

66

67

68

69

70

71

72

73

EXAMPLE 3

Preparation of (E)-4-pentylphenyl trans4-(2-(trans-4-pentylcyclohexyl)vinyl)cyclohexanecarboxylate (Compoundexpressed by the general formula (1) wherein both Ra and Rb are C₅H₁₁, mis 0, both A₁ and A₂ are trans-1,4-cyclohexylene group, A₃ is1,4-phenylene group, Z₁ is —CH═CH—, and Z₂ is —COO—; Compound No. 74)

(E)-trans-4-(2-(trans-4-pentylcyclohexyl)vinyl)cyclohexane carboxylicacid in an amount of 1.1 g (3.6 mmol), 0.7 g (4.3 mmol) of4-pentylphenol, 0.1 g (1.1 mmol) of DMAP, and 20 ml of dichloromethanewere mixed. To this mixture was added dropwise 4 ml of solution of 1.0 g(4.7 mmol) of DCC in dichloromethane while being cooled with ice in 5min, and stirred as it was for 12 hours. Separated crystals werefiltered off. To the filtrate was added 70 ml of toluene, washed with2N-NaOH five times and with water thrice, and then dried over anhydrousmagnesium sulfate. The solvent was distilled off under a reducedpressure. The residue thus obtained was subjected to silica gel columnchromatography (eluent: toluene/heptane=1/1) to obtain 1.5 g of a crude(E)-4-pentylphenyltrans-4-(2-(trans-4-pentylcyclohexyl)vinyl)cyclohexanecarboxylate. Thiscrude product was recrystallized from a mixed solvent of heptane/diethylether to obtain 1.2 g of the subjective compound (yield 74.7%).

This compound exhibited liquid crystal phase and its phase transitiontemperatures were as follows:

C 66.7˜67.6 S_(A) 157.0 N 183.7 Iso

Further, mass spectrum data of this compound well supported itsstructure.

Mass spectrometry: 452 (M⁺); H¹NMR (CDCl₃, TMS internal standard); δ(ppm); 0.81-2.67 (m, 41H); 5.30-5.35 (m,2H); 6.94 (m, 2H); 7.17 (d, 2H).

According the methods of Example 3, the following compounds (CompoundsNo. 75 to No. 108) are prepared.

No. 75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

EXAMPLE 4

Preparation of (E)-3, 5-difluoro-4-trifluoromethoxyphenyl4-(2-(trans-4-(trans-4-propylcyclohexyl)cyclohexyl)vinyl) benzoate(Compound expressed by the general formula (1) wherein Ra is C₃H₇, Rb isOCF₃, m is 1, both A₁ and A₂ are trans-1,4-cyclohexylene group, A₃ is1,4-phenylene group, A₄ is 3-fluoro-1,4-phenylene group, Z₁ is acovalent bond, Z₂ is —CH═CH—, and Z₃ is —COO—; Compound No. 109)

(E)-4-(2-(trans-4-(trans-4-pentylcyclohexyl)cyclohexyl)vinyl)benzoicacid in an amount of 1,3 g (3.7 mmol), 0.8 g (3.7 mmol) of3,5-difluoro-4-trifluoromethoxyphenol, 0.1 g (1.1 mmol) of DMAP, and 30ml of dichloromethane were mixed. To this mixture was added dropwise 5ml of solution of 1.0 g (4.8 mmol) of DCC in dichloromethane while beingcooled with ice in 5 min, and stirred as it was for 12 hours. Separatedcrystals were filtered off, and 80 ml of toluene was added to thefiltrate, washed with 2N-NaOH five times and with water thrice, and thendried over anhydrous magnesium sulfate. The solvent was distilled offunder a reduced pressure. The residue thus obtained was subjected tosilica gel column chromatography (eluent: toluene) to obtain 1.7 g of acrude (E)-3,5-difluoro-4-trifluoromethoxyphenyl4-(2-(trans-4-(trans-4-propylcyclohexyl)cyclohexyl)vinyl)benzoate.

This crude product was recrystallized from a mixed solvent ofheptane/ethyl acetate to obtain 1.5 g of the subjective compound (yield74.3%).

Mass spectrum data of this compound well supported its structure.

Mass spectrometry: 550 (M⁺).

According the methods of Example 4, the following compounds (CompoundsNo. 110 to No. 149) are prepared.

No. 110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

Example in which the liquid crystalline compounds of the presentinvention were used as component of liquid crystal compositions areshown below. In each of Use Examples, NI indicates a phase transitiontemperature of nematic phase-isotropic phase (° C.); Δε, dielectricanisotropy value; Δn, optical anisotropy value; η, viscosity at 20° C.(mPa·s); and V₁₀, threshold voltage (V).

EXAMPLE 5 (Use Example 1)

Liquid crystal composition ZLI-1132 (mother liquid crystal) produced byMerck and comprising the following cyanophenyl-cyclohexane type liquidcrystalline compounds in the amount each shown below

4-(trans-4-propylcyclohexyl)benzonitrile 24% by weight,4-(trans-4-pentylcyclohexyl)benzonitrile 36% by weight,4-(trans-4-heptylcyclohexyl)benzonitrile 25% by weight, and4-(trans-4-pentylcyclohexyl)-4′-cyanobiphenyl 15% by weight

have the following physical properties:

NI: 72.4, Δε: 11.0, Δn: 0.137, η: 26.7, V₁₀ at a cell thickness of 9 μm:1.78

To the mother liquid crystal (ZLI-1132) in an amount of 85% by weightwas mixed 15% by weight of (E)-3,5-difluoro-4-cyanophenyl4-(2-(trans-4-propylcyclohexyl)vinyl)benzoate (Compound No. 1) toprepare a liquid crystal composition. Physical properties of this liquidcrystal composition were as follows:

NI: 86.5, Δε: 16.1, Δn: 0.217, η: 43.7, V₁₀ at a cell thickness of 8.8μm: 1.42

While this liquid crystal composition was left in a freezer at −20° C.,separation of crystals was not observed even after the lapse of 60 days.

EXAMPLE 6 (Use Example 2)

Example 5 was repeated to prepare a liquid crystal composition with theexception that (E)-3-fluoro-4-trifluoromethoxyphenyltrans-4-(2-(trans-4-pentylcyclohexyl)vinyl)cyclohexanecarboxylate(Compound No. 51) was used in place of (E)-3,5-difluoro-4-cyanophenyl4-(2-(trans-4-propylcyclohexyl)vinyl)benzoate (Compound No. 1). Physicalproperties of this liquid crystal composition were as follows:

NI: 78.5, Δε: 10.4, Δn: 0.129, η: 28.1, V₁₀ at a cell thickness of 8.7μm: 1.77

While this liquid crystal composition was left in a freezer at −20° C.,separation of crystals was not observed even after the lapse of 60 days.

EXAMPLE 7 (Use Example 3)

Physical properties of the primary liquid crystal composition shown inComposition Example 17 were as follows:

NI: 100.6, Δε: 10.3, Δn: 0.170, η: 25.5, V₁₀: 1.36

To the primary liquid crystal composition described above in an amountof 100 parts by weight was added and dissolved 0.8 part of the opticallyactive compound expressed by the formula (Op-4) described above toprepare a secondary liquid crystal composition, and the pitch (P) of thesecondary liquid crystal composition was determined. The result was asfollows:

P=10.5 μm

EXAMPLE 8 (Use Example 4)

Physical properties of the primary liquid crystal composition shown inComposition Example 18 were as follows:

NI: 98.4, Δε: 30.2, Δn: 0.152, η: 88.0, V₁₀: 0.99

EXAMPLE 9 (Use Example 5)

Physical properties of the primary liquid crystal composition shown inComposition Example 19 were as follows:

NI: 94.5, Δε: 6.3, Δn: 0.200, η: 36.1, V₁₀: 2.41

EXAMPLE 10 (Use Example 6)

Physical properties of the primary liquid crystal composition shown inComposition Example 20 were as follows:

NI: 66.9, Δε: 11.9, Δn: 0.118, η: 40.6, V₁₀: 0.97

EXAMPLE 11 (Use Example 7)

Physical properties of the primary liquid crystal composition shown inComposition Example 21 were as follows:

NI: 81.0, Δε: 9.2, Δn: 0.142, η: 20.7, V₁₀: 1.42

EXAMPLE 12 (Use Example 8)

Physical properties of the primary liquid crystal composition shown inComposition Example 22 were as follows:

NI: 104.6, Δε: 25.1, Δn: 0.128, η: 39.2, V₁₀: 0.82

EXAMPLE 13 (Use Example 9)

Physical properties of the primary liquid crystal composition shown inComposition Example 23 were as follows:

NI: 92.4, Δε: 27.9, Δn: 0.142, η: 40.7, V₁₀: 1.21

EXAMPLE 14 (Use Example 10)

Physical properties of the primary liquid crystal composition shown inComposition Example 24 were as follows:

NI: 69.1, Δε: 13.7, Δn: 0.119, η: 35.7, V₁₀: 0.86

EXAMPLE 15 (Use Example 11)

Physical properties of the primary liquid crystal composition shown inComposition Example 25 were as follows:

NI: 68.4, Δε: 6.2, Δn: 0.157, η: 20.2, V₁₀: 1.89

EXAMPLE 16 (Use Example 12)

Physical properties of the primary liquid crystal composition shown inComposition Example 26 were as follows:

NI: 103.2, Δε: 4.6, Δn: 0.100, η: 19.6, V₁₀: 2.54

EXAMPLE 17 (Use Example 13)

Physical properties of the primary liquid crystal composition shown inComposition Example 27 were as follows:

NI: 110.4, Δε: 9.7, Δn: 0.099, η: 34.8, V₁₀: 1.15

To the primary liquid crystal composition described above in an amountof 100 parts by weight was added and dissolved 0.3 part of the opticallyactive compound expressed by the formula (Op-8) described above toprepare a secondary liquid crystal composition, and the pitch (P) of thesecondary liquid crystal composition was determined. The result was asfollows:

P=77.6 μm

EXAMPLE 18 (Use Example 14)

Physical properties of the primary liquid crystal composition shown inComposition Example 28 were as follows:

NI: 94.6, Δε: 11.3, Δn: 0.122, 17: 37.2, V₁₀: 0.81

EXAMPLE 19 (Use Example 15)

Physical properties of the primary liquid crystal composition shown inComposition Example 29 were as follows:

NI: 96.4, Δε: 7.4, Δn: 0.133, η: 26.0, V₁₀: 1.62

EXAMPLE 20 (Use Example 16)

Physical properties of the primary liquid crystal composition shown inComposition Example 30 were as follows:

NI: 99.6, Δε: 9.3, Δn: 0.117, η: 36.2, V₁₀: 1.59

EXAMPLE 21 (Use Example 17)

Physical properties of the primary liquid crystal composition shown inComposition Example 31 were as follows:

NI: 88.2, Δε: 9.6, Δn: 0.096, η: 21.5, V₁₀: 1.05

EXAMPLE 22 (Use Example 18)

Physical properties of the primary liquid crystal composition shown inComposition Example 32 were as follows:

NI: 101.7, Δε: 8.5, Δn: 0.133, η: 17.6, V₁₀: 2.06

EXAMPLE 23 (Use Example 19)

Physical properties of the primary liquid crystal composition shown inComposition Example 33 were as follows:

NI: 85.8, Δε: 10.8, Δn: 0.094, η: 31.6, V₁₀: 1.94

While primary liquid crystal compositions shown in Examples 7 through 23were left in separate freezers at −20° C., respectively, development ofsmectic phase or separation of crystals was not observed after the lapseof 60 days with any of the primary liquid crystal compositions.

COMPARATIVE EXAMPLE 1

Example 6 was repeated with the exception that the compound containingno alkenylene group and expressed by the formula (d)

was used in place of (E)-3-fluoro-4-trifluoromethoxyphenyltrans-4-(2-(trans-4-pentylcyclohexyl)vinyl)cyclohexanecarboxylate(Compound No. 51), to obtain a liquid crystal composition. Physicalproperties of this liquid crystal composition were as follows:

Δε: 10.5, η: 28.8, V₁₀ at a cell thickness of 8.7 μm: 1.78

From the comparison of these physical properties with those shown inExample 6, it can be understood that the compound (Compound No. 51)(comprising alkenylene group) of the present invention has a lowerviscosity than the compound comprising no alkenylene group and expressedby the formula (d), and that the compound of the present invention has alower threshold voltage (V₁₀) than the compound of the formula (d)whereas the former has a lower Δε than the latter. These results arecontrary to the ones expected based on technical common sense (referenceis made to the Reference Example described below), and thus thoseresults were unable to anticipate.

REFERENCE EXAMPLE

Liquid crystal composition ZLI-1083 (base mixture) produced by Merck andcomprising the following cyanophenyl-cyclohexane type liquid crystallinecompounds in the amount each shown below

4-(trans-4-propylcyclohexyl)benzonitrile 30% by weight,4-(trans-4-pentylcyclohexyl)benzonitrile 40% by weight, and4-(trans-4-heptylcyclohexyl)benzonitrile 30% by weight,

have the following physical properties:

NI: 52.3, Δε: 10.7, Δn: 0.119, η: 21.7, V₁₀ at a cell thickness of 9 μm:1.60

To compositions each consisting of the base mixture (ZLI-1083) in anamount of 85% by weight was mixed 15% by weight of either compoundexpressed by the formula (e) or (f)

as known reference compound, to prepare two final liquid crystalcompositions. Physical properties of the final liquid crystalcompositions obtained were as follows:

η Δε V₁₀ Compound expressed by 21.2 10.4 1.59 the formula (e) Compoundexpressed by 23.3 10.6 1.82 the formula (f)

As will clearly be seen from the results shown above, compounds in whichalkenylene group is introduced between six-membered rings (cf. compoundexpressed by the formula (f)) have a higher viscosity and a higherthreshold voltage (V₁₀) compared with the compounds in which alkenylenegroup is not introduced (cf. compound expressed by the formula (e)).

INDUSTRIAL APPLICABILITY

As described above, the compounds of the present invention are wide intemperature range of liquid crystal phase, are low in viscosity, have alow threshold voltage, are excellent in stability, are readily mixedwith various liquid crystal materials, and are excellent in solubilityeven at low temperatures.

Accordingly, when the compounds of the present invention are used ascomponent of liquid crystal compositions, liquid crystal compositionshaving the characteristics described above can be produced, and besides,liquid crystal compositions having desired physical properties can beprovided by selecting proper rings, substituents and/or bonding groupsas molecule constituting element of the compounds.

We claim:
 1. A vinylene compound expressed by the general formula (1)Ra—A₁—Z₁—A₂—Z₂—A₃—(Z₃—A₄)_(m)—Rb  (1) wherein Ra represents an alkylgroup having 1 to 20 carbon atoms one or more —CH₂— in which alkyl groupmay be replaced by —O—, —S—, —CO—, —CH═CH—, or —C≡C—, but in no case —O—and/or —S— continues, and one or more hydrogen atoms in which alkylgroup may be replaced by a halogen atom; Rb represents Ra, a halogenatom, or cyano group; A₁, A₂, A₃, and A₄ independently representtrans-1,4-cyclohexylene group, cyclohexenylene group, 1,4-phenylenegroup one or more hydrogen atoms on which ring may be replaced by ahalogen atom or cyano group, pyridine-2,5-diyl group,pyrimidine-2,5-diyl group, or 1,3-dioxane-2,5-diyl group; and Z₁, Z₂,and Z₃ independently represent a vinylene group, —COO—, —OCO—, —(CH₂)₂—,—C≡C—, —CH₂O—, —OCH₂—, or a covalent bond provided that at least one ofZ₁ to Z₃ is a vinylene group a ring pair holding the vinylene grouptherebetween is under the following condition, and at least one of Z₁ toZ₃ represents —COO— or —OCO—; and m is 0 or 1; condition for the ringpair: at least one of the rings of the pair is selected fromtrans-1,4-cyclohexylene group, cyclohexenylene group, or1,3-dioxane-2,5-diyl group.
 2. The vinylene compound according to claim1 wherein m is
 0. 3. The vinylene compound according to claim 1 whereinm is
 1. 4. The vinylene compound according to claim 2 wherein Z₁ isvinylene.
 5. The vinylene compound according to claim 2 wherein Z₂ isvinylene.
 6. The vinylene compound according to claim 3 wherein Z₁ isvinylene.
 7. The vinylene compound according to claim 3 wherein Z₂ isvinylene.
 8. The vinylene compound according to claim 4 wherein A₁ andA₂ are independently trans-1,4-cyclohexylene group, or 1,4-phenylenegroup one or more hydrogen atoms on which ring may be replaced by ahalogen atom or cyano group.
 9. The vinylene compound according to claim6 wherein A₁ and A₂ are independently trans-1,4-cyclohexylene group, or1,4-phenylene group one or more hydrogen atoms on which ring may bereplaced by a halogen atom or cyano group.
 10. The vinylene compoundaccording to claim 5 wherein A₁ and A₂ are independentlytrans-1,4-cyclohexylene group, or 1,4-phenylene group one or morehydrogen atoms on which ring may be replaced by a halogen atom or cyanogroup.
 11. The vinylene compound according to claim 7 wherein A₁ and A₂are independently trans-1,4-cyclohexylene group, or 1,4-phenylene groupone or more hydrogen atoms on which ring may be replaced by a halogenatom or cyano group.
 12. A liquid crystal composition comprising atleast two components, at least one of which is a vinylene compounddefined in any one of claims 1 to 9, 10 or
 11. 13. A liquid crystalcomposition comprising, as a first component, at least one vinylenecompound defined in any one of claims 1 to 9, 10 11 and comprising, as asecond component, at least one compound selected from the groupconsisting of the compounds expressed by any one of the general formulas(2), (3), and (4)

wherein R₁ represents an alkyl group having 1 to 10 carbon atoms; X₁represents F, Cl, OCF₃, OCF₂H, CF₃, CF₂H, or CFH₂; L₁, L₂, L₃, and L₄independently represent H or F; Z₄ and Z₅ independently represent—(CH₂)₂—, —CH═CH—, or a covalent bond; and a is 1 or
 2. 14. A liquidcrystal composition comprising, as a first component, at least onevinylene compound defined in any one of claims 1 to 9, 10 or 11 andcomprising, as a second component, at least one compound selected fromthe group consisting of the compounds expressed by any one of thegeneral formulas (5), (6), (7), (8), and (9)

wherein R₂ represents F, an alkyl group having 1 to 10 carbon atoms, oran alkenyl group having 2 to 10 carbon atoms any methylene group (—CH₂—)in which alkyl or alkenyl group may be replaced by oxygen atom (—O—),but in no case two or more methylene groups are continuously replaced byoxygen atom; ring A represents trans-1,4-cyclohexylene group,1,4-phenylene group, or 1,3-dioxane-2,5-diyl group; ring B representstrans-1,4-cyclohexylene group, 1,4-phenylene group, orpyrimidine-2,5-diyl group; ring C represents trans-1,4-cyclohexylenegroup or 1,4-phenylene group; Z₆ represents —(CH₂)₂—, —COO—, or acovalent bond; L₅ and L₆ independently represent H or F; and b and c areindependently 0 or 1,

wherein R₃ represents an alkyl group having 1 to 10 carbon atoms, L₇represents H or F; and d is 0 or 1,

wherein R₄ represents an alkyl group having 1 to 10 carbon atoms; ring Dand ring E independently represent trans-1,4-cyclohexylene group or1,4-phenylene group; Z₇ and Z₈ independently represent —COO— or acovalent bond; Z₉ represents —COO— or —C≡C—; L₈ and L₉ independentlyrepresent H or F; X₂ represents F, OCF₃, OCF₂H, CF₃, CF₂H, or CFH₂; ande, f, and g are independently 0 or 1,

wherein R₅ and R₆ independently represent an alkyl group having 1 to 10carbon atoms or an alkenyl group having 2 to 10 carbon atoms anymethylene group (—CH₂—) in which alkyl or alkenyl group may be replacedby oxygen atom (—O—), but in no case two or more methylene groups arecontinuously replaced by oxygen atom; ring G representstrans-1,4-cyclohexylene group, 1,4-phenylene group, orpyrimidine-2,5-diyl group; ring H represents trans-1,4-cyclohexylenegroup or 1,4-phenylene group; Z₁₀ represents —C≡C—, —COO—, —(CH₂)₂—,—CH═CH—C≡C—, or a covalent bond; and Z₁₁ represents —COO— or a covalentbond,

wherein R₇ and R₈ independently represent an alkyl group having 1 to 10carbon atoms or an alkenyl group having 2 to 10 carbon atoms anymethylene group (—CH₂—) in which alkyl or alkenyl group may be replacedby oxygen atom (—O—), but in no case two or more methylene group arecontinuously replaced by oxygen atom; ring I representstrans-1,4-cyclohexylene group, 1,4-phenylene group, orpyrimidine-2,5-diyl group; ring J represents trans-1,4-cyclohexylenegroup, 1,4-phenylene group one or more hydrogen atoms on which ring maybe replaced by F, or pyrimidine-2,5-diyl group; ring K representstrans-1,4-cyclohexylene group or 1,4-phenylene group; Z₁₂ and Z₁₄independently represent —COO—, —(CH₂)₂—, or a covalent bond; Z₁₃represents —CH═CH—, —C≡C—, —COO—, or a covalent bond; and h is 0 or 1.15. A liquid crystal display device comprising the liquid crystalcomposition defined in claim
 12. 16. A liquid crystal display devicecomprising the liquid crystal composition defined in claim
 13. 17. Aliquid crystal display device comprising the liquid crystal compositiondefined in claim
 14. 18. A liquid crystal composition comprising, as afirst component, at least one vinylene compound defined in any one ofclaims 1 to 9, 10 or 11, comprising, as a part of a second component, atleast one compound selected from the group consisting of the compoundsexpressed by any one of the general formulas (2), (3), and (4), andcomprising, as another part of the second component, at least onecompound selected from the group consisting of the compounds expressedby any one of the general formulas (5), (6), (7), (8), and (9)

wherein R₁ represents an alkyl group having 1 to 10 carbon atoms; X₁represents F, Cl, OCF₃, OCF₂H, CF₃, CF₂H, or CFH₂; L₁, L₂, L₃, and L₄independently represent H or F; Z₄ and Z₅ independently represent—(CH₂)₂—, —CH═CH—, or a covalent bond; and a is 1 or 2,

wherein R₂ represents F, an alkyl group having 1 to 10 carbon atoms, oran alkenyl group having 2 to 10 carbon atoms any methylene group (—CH₂—)in which alkyl or alkenyl group may be replaced by oxygen atom (—O—),but in no case two or more methylene groups are continuously replaced byoxygen atom; ring A represents trans-1,4-cyclohexylene group,1,4-phenylene group, or 1,3-dioxane-2,5-diyl group; ring B representstrans-1,4-cyclohexylene group, 1,4-phenylene group, orpyrimidine-2,5-diyl group; ring C represents trans-1,4-cyclohexylenegroup or 1,4-phenylene group; Z₆ represents —(CH₂)₂—, —COO—, or acovalent bond; L₅ and L₆ independently represent H or F; and b and c areindependently 0 or 1,

wherein R₃ represents an alkyl group having 1 to 10 carbon atoms, L₇represents H or F; and d is 0 or 1,

wherein R₄ represents an alkyl group having 1 to 10 carbon atoms; ring Dand ring E independently represent trans-1,4-cyclohexylene group or1,4-phenylene group; Z₇ and Z₈ independently represent —COO— or acovalent bond; Z₉ represents —COO— or —C≡C—; L₈ and L₉ independentlyrepresent H or F; X₂ represents F, OCF₃, OCF₂H, CF₃, CF₂H, or CFH₂; ande, f, and g are independently 0 or 1,

wherein R₅ and R₆ independently represent an alkyl group having 1 to 10carbon atoms or an alkenyl group having 2 to 10 carbon atoms anymethylene group (—CH₂—) in which alkyl or alkenyl group may be replacedby oxygen atom (—O—), but in no case two or more methylene groups arecontinuously replaced by oxygen atom; ring G representstrans-1,4-cyclohexylene group, 1,4-phenylene group, orpyrimidine-2,5-diyl group; ring H represents trans-1,4-cyclohexylenegroup or 1,4-phenylene group; Z₁₀ represents —C≡C—, —COO—, —(CH₂)₂—,—CH═C—H—C≡C—, or a covalent bond; and Z₁₁ represents —COO— or a covalentbond,

wherein R₇ and R₈ independently represent an alkyl group having 1 to 10carbon atoms or an alkenyl group having 2 to 10 carbon atoms anymethylene group (—CH₂—) in which alkyl or alkenyl group may be replacedby oxygen atom (—O—), but in no case two or more methylene group arecontinuously replaced by oxygen atom; ring I representstrans-1,4-cyclohexylene group, 1,4-phenylene group, orpyrimidine-2,5-diyl group; ring J represents trans-1,4-cyclohexylenegroup, 1,4-phenylene group one or more hydrogen atoms on which ring maybe replaced by F, or pyrimidine-2,5-diyl group; ring K representstrans-1,4-cyclohexylene group or 1,4-phenylene group; Z₁₂ and Z₁₄independently represent —COO—, —(CH₂)₂—, or a covalent bond; Z₁₃represents —CH═CH—, —C≡C—, —COO—, or a covalent bond; and h is 0 or 1.19. A liquid crystal display device comprising the liquid crystalcomposition defined in claim 18.